«Industrial regions of Russia», March of 2004
Novatek-Electro: The Problem of Electric Energy Consumer Protection
Against the Mains Faults Has Been Solved
One of the important prerequisites for the successful work of industrial
and energy plants, transportation system and public-utility enterprises
is the stability and quality assurance of power consumption. To that
end the various types of relay protection are used in power supply systems
of these installations. In particular, the devices provide load protection
when phase loss, phase imbalance, incorrect phase sequence occur or
a voltage goes outside pre-specified voltage range and so forth. The
relay protection is used not only directly at the terminal protected
installation (for instance, at an inductive motor (IM)) but also in
the special electric circuits, including automatic throw-over circuit-breakers.
Unfortunately most relay devices produced in the factories of the Commonwealth
of Independent States were developed in the USSR. The devices feature
limited capabilities and a low reliability because out-of-date accessories
are used. So they don't provide the complete electric installation
protection.
Modern foreign relays excel greatly the soviet counterparts but unfortunately
they are very expensive for the mass application.
That's why the NOVATEK-ELECTRO company has developed and brought
to a commercial level the whole series of modern relay devices that
are at an equal level functionally to the foreign relays but due to
the advanced technology and effective solutions cost considerably less.
The most popular and best-selling products are:
-- RNPP-301 and RNPP-311 Three-Phase Voltage, Phase Imbalance and Phase
Sequence Relays;
-- RN-101, RN-111 Single-Phase Voltage Relays;
-- RN-112 Universal Minimum/Maximum Voltage Relays;
-- REV-201 Two-Channel Time Delay Relays;
-- PEF-301 Universal Automatic Electronic Phase Switches;
-- UBZ-301 Universal Induction Motors Protection Units.
Principal difference of the devices we produce is the application of the latest achievements in modern digital microprocessor-based technology that allows to digitize analogue signals and to make an appropriate decision according to the elaborated algorithm. Besides, all the products incorporate the modern import accessories from leading worldwide manufacturers.
This approach to the development and production of our products enabling
to meet the broad spectrum of consumer's demands on the one part
and to provide a high reliability of the products on the other part
gives to our products a number of advantages against all the rest traditional
analogue devices in the market.
The following describes the key advantages:
-- the application of complicated signal processing algorithms (R.M.
S. current and R.M.S. voltage computation, special data processing filters
etc.) is provided;
-- the simplicity of many adjustments for different parameters in a
manual mode is provided;
-- the separate performance algorithms for different types of faults
(the automatic reset subject to the user-specified terms (permitted/inhibited),
the adjustable time delay start and/or stop according to the fault type,
the accelerated trip in the event of extremely abnormal condition etc.);
-- the discriminative fault type indication: fault conditions are displayed
by special LEDs indicating the specific cause of the occurring fault;
- the operate stability over a wide range of environmental parameters.
Let's examine in details some of the features of the relays we
produce.
Three phase voltage, phase imbalance and phase sequence relays
Three-phase voltage and phase monitoring relays are designed for the
protection of the most essential services. They provide cost-effective
protection against equipment failure caused by voltage faults on 3-Phase
systems, i.e. they are adapted to protect three-phase loads from unallowable
variations in the mains voltage, phase loss and phase imbalance, phase
"coincidence" and incorrect phase sequence. They are efficiently
applicable for the protection of refrigerating and air-conditioning
installations, compressor plants and other equipment with an electric
motor load. They are also used in the devices that call for continuous
monitoring of the mains voltage, three phase lines for quality and voltage
presence, e.g. in the automatic throw-over circuit-breakers.
Hysteresis is about 5V in all the relays. The operational capability
range is 30 -150% of the nominal voltage. Deep undervoltage (when one
or more phase voltage value drops 30 V below the user-preset minimum
voltage threshold) and/or abrupt overvoltage (when one or more phase
voltage 30V exceeds the user-preset maximum voltage threshold) automatically
make the relay to trip with acceleration. The relay will reset automatically
activating a load with user-specified time delay on return to normal
operating conditions when voltage values regenerated, reaching the level
set by hysteresis. The relays are compact, rugged and have a small weight.
All the relays are mounted on the standard DIN rail.
The relays are connected in parallel to load and they energize a magnetic
starter coil that's why the relay operation is practically independent
on load power. Two groups of independent contacts (one pair is N.C.
contacts, another pair is N.O. contacts) at the relay output terminals
switch the load up to 5A power.
RNPP-301
Three-Phase Voltage and Phase Monitoring Relay
This is a microprocessor-based multifunction mains voltage monitor.
Developed on the base of modern microprocessor technology the device
is offering the unique set of services that is able to replace several
traditional devices.
The RNPP-301 monitor provides:
-- full multi-fault protection;
-- an additional function of monitoring for the magnetic starter power
contacts switch (position at no-load and under load);
-- an unique option of two control modes that can be selected as phase
or line voltage monitoring;
-- monitoring of the tolerable RMS phase/line voltage level and tripping
for RMS voltage;
-- independent setting adjustments for the minimum/maximum voltage thresholds;
-- monitoring of the correct phase sequence and phase "non-coincidence"
(the phases are supposed to be coinciding when a load is energized not
from two different phases but instead from one and the same phase);
-- monitoring of three phase lines for voltage presence and the mains
voltage symmetry with phase imbalance adjustable setting;
-- the load (380V/50Hz) de-energization after user-set trip delay (Toff)
has expired through the opening the magnetic starter coil power curcuit
(A.C and D.C. electric curcuit switching) when fault conditions occur;
-- the mains voltage quality monitoring after the relay had tripped
and did reset automatically with the user-set reset delay (Ton) upon
the voltage parameters regeneration;
-- fault conditions are displayed by special LEDs indicating the specific
cause of the occurring mains voltage fault;
-- the LED is provided indicating that the magnetic starter power contacts
didn't switch;
-- all relay states will be displayed via LEDs: LED indicators show
when the relay and the load are on.
RNPP-311
Three-Phase Voltage and Phase Monitoring Relay
The RNPP-311 is the best-selling product
of our company, because it offers the services sufficient for the full
mains voltage monitoring, but due to ingenious circuitry solutions it
is considerably cheaper than corresponding devices from other producers.
This is the monitor with extremely low price, adequate set of functions,
wide application, high reliability, few needs in the service, operation
simplicity and low power demand.
The RNPP-311 monitor provides:
-- monitoring of correct phase sequence and phase "non-coincidence";
-- monitoring of 3-Phase lines for voltage presence and the mains voltage
symmetry;
-- adjustable trip setting for the minimum/the maximum voltage;
-- load 380V/50Hz de-energization (not throwing on) through the opening
the magnetic starter coil power circuit when there are the unallowable
mains voltage parameters;
-- different decision-making algorithms for different types of faults
that allow to ignore transient starting voltage drops, but enable the
relay to trip with acceleration in the event of serious voltage faults;
-- the mains voltage quality monitoring after the relay had tripped
and did reset automatically with the user-set reset delay (Ton) upon
the voltage parameters regeneration;
-- combined indication for all types of the mains voltage faults and
LED indication for voltage presence on each phase.
The relay has the following features:
-- it's self-powered by the three-phase voltage to be monitored;
-- there are two groups of two-way break-before-make contacts in the
output;
-- magnetic starter coil supply circuit and power circuits are conductively
isolated;
-- all three phases are monitored individually;
-- voltage signals are digitalized;
-- due to the digital technology the adjustable and fixed trip settings
of the relay are calibrated quite accurate and don't depend on
environment factors, so the relay doesn't call for additional
adjustments and controller settings;
-- the accurate voltage adjustment over a broad range;
-- the range of adjustable & fixed setting values can be changed
at the customer's request;
-- indication of voltage presence on each phase; indication of tripping
on fault conditions;
-- different decision-making algorithms for each type of fault;
-- immunity to transient starting voltage drops that cause nuisance
tripping is provided;
-- accelerated load de-energization when there are serious fault conditions;
-- hysteresis for Umax/Umin is within 6-7V;
-- operate capability range is 30-150% of nominal voltage when at least
one phase is present;
-- compactness and small weight;
-- mounted on a standard DIN rail;
THE RNPP-311 MODIFICATIONS
At the customer's RFP we designed two modifications of the RNPP-311
monitor on the base of the standard RNPP-311 model. Due to microprocessor
based technology the device circuitry remained almost unchanged; the
modifications were made in the program recorded in the microcontroller's
memory.
1. RNPP-311 (U-f) TWO CHANNEL VOLTAGE RELAY
The RNPP-311 (U-f) modification is a two- channel voltage relay designed
for usage together with Diesel-generators. The device provides all voltage
monitor functions of the standard RNPP-311 and in addition it monitors
the mains frequency. The modification is designed to provide load 380V/50Hz
de-energization when:
-- there are unallowable voltage fluctuations in the mains that last
? 0.02 sec, the mains voltage peak asymmetry (phase unbalance), phase
loss, incorrect phase sequence and phase "coincidence" occur
(U channel);.
-- the mains frequency exceeds/drops below the set range (f channel).
2. RNPP-311 (Megafon) TWO CHANNEL VOLTAGE RELAY
The RNPP-311 (Megafon) is designed to provide 3-phase 380V/50Hz system
monitoring and to signalize the phase or phases where normal operating
voltage are not present. Unlike the standard RNPP-311 the Megafon doesn't
monitor phase sequence, phase "coincidence" and phase unbalance.
It has two independent output channels.
The 1st channel signalizes that there is a complete absence of voltage
on all three phases in 380V/50Hz lines and/or that the voltages on all
phases fall outside the preset Over/Under trip thresholds.
The 2nd channel signalizes that voltage is not present on any one or
two phases in 380V/50Hz lines and/or that overvoltage/undervoltage on
these phases occurs greater than the trip settings.
Single-Phase Voltage Relays
The RN-101 and RN-111single phase voltage relays are designed for protection
of an industrial/appliance single-phase 220V/50Hz load against unallowable
voltage variations in the mains. The relays have a wide range of different
parameter adjustments, including reset delay adjustments for the protection
of refrigerating, compressor and air-conditioning equipment.
Hysteresis is about 5V in all the relays. The operational capability
range is 30 -150% of the nominal voltage. Deep undervoltage and/or abrupt
overvoltage entail the automatic accelerated relay tripping. On return
to normal operating conditions when the voltage parameters regenerate,
the relay will reset automatically and the load will be energized. The
relays are compact, rugged and have a small weight.
The relays can be used both as the self-dependent switching apparatus
and as control devices for switching apparatus, for instance, magnetic
starters.
RN-101
Single-Phase Voltage Relay
The RN-101 voltage relay is designed to de-energize an industrial/appliance
single-phase 220V/50Hz load of 3.5 kWt (to 16A) power when there are
unallowable voltage variations in the mains. This microprocessor protection
device offers a simple and cost-effective solution for the local protection
of electric loads.
This relay is also suitable for the protection elevators and any other
device sensitive to overvoltage and undervoltage fluctuations. The relay
is connected in series with load, i. e. the relay is plugged in at a
socket-outlet directly and load is thrown on at a female connector of
the relay.
When the relay trips due to unallowable overvoltage/undervoltage, a
switching device built-in the relay de-energizes the load.
The relay has three independent controls:
-- trip threshold for the minimum voltage: 160-210V;
-- trip threshold for the maximum voltage: 230-280V:
-- automatic reset delay: 5-900 sec.
The RN-101 provides:
-- a wide range of adjustable trip thresholds (Umax, Umin, reset delay);
-- the fixed trip delay to ignore starting voltage drops that cause
nuisance tripping when Umin is reached ;
-- the relay tripping with 0.1 sec time delay when deep undervoltage/abrupt
overvoltage more than 30V from threshold settings occurs;
-- LED indication for the relay status;
-- trip/reset hysteresis for Umax/Umin that is approximately 5V. It
means that if the relay had tripped due to voltage drop below Umin threshold
and the load was de-energized, the relay will reset automatically and
energize the load when the voltage exceeds 5V above Umin threshold (reaching
the level set by hysteresis) with reset delay Ton.
The relays with another trip setting ranges and their fixed values can
be supplied, on request.
RN-111
Single-Phase Voltage Relay
The RN-111 relay is a microprocessor-based single-phase
mains voltage monitor that offers all the RN-101 voltage relays services
but is encased and mounted on DIN-rails.The RN-111 Voltage Relays are designed to de-energize any power appliance/ industrial single-phase load 220V/ 50Hz when there are abnormal voltage variations in the mains and to energize this load automatically on return to normal operating conditions when the mains voltage parameters regenerate:
-- if load power is below 3,5 kW (up to 16A) de-energization is performed directly through the relay output contacts which are connected in series with the load power supply;
-- if load power is over 3,5 kW (16A) de-energization is effected by the magnetic starter of the corresponding power (MS is not supplied in the complete set) that has the relay output contacts to be connected in series with its coil power supply.
The relay has three independent controls:
-- trip threshold for the maximum voltage, Umax;
-- trip threshold for the mimimum voltage, Umin;
-- reset delay, Ton.
The RN-111 has the following features:
-- trip settings (Umax, Umin, Reset delay) are adjusted in a wide range;
-- high accuracy for trip thresholds;
-- the fixed trip delay is provided to ignore starting voltage drops
that cause nuisance tripping of the relay when Umin is reached;
-- the relay trips with 0.1 sec time delay when deep undervoltage/abrupt
overvoltage more than 30V from threshold settings occurs;
-- LED indicators of mains voltage in the input and voltage in the output;
quite a high power of output contacts that enables to extend the relay
application range and in some instances to abandon auxiliary switching
devices;
-- trip/reset hysteresis for Umax/Umin is approximately 5V;
-- two-way break-before make contact group in the output allows alarm
signalling to operate;
-- the relays with another trip setting ranges and their fixed values
can be supplied, on request;
-- compactness, low power demand and small weight of the relay;
-- mounted on a standard DIN rail.
RN-112
Universal Minimum/Maximum Voltage Relay
The RN-112 universal electronic maximum/minimum voltage relays are
designed to monitor allowable voltage value and voltage presence with
rated parameters 100V/ 50Hz as well as to switch electric curcuits in
protection and automation devices of electric installations where the
nominal voltage is above 1000V.
The relay provides adjustments of trip settings for voltage and time
delay when voltage threshold values are reached. The relay provides
three modes of operation:
n the minimum voltage relay mode (the relay trips only when the minimum
voltage threshold is reached);
n the maximum voltage relay mode (the relay trips only when the maximum
voltage threshold is reached);
n the symmetry settings mode (the relay trips when both the maximum
and the minimum voltage thresholds are reached).
The RN-112 has the following features:
-- the digital microprocessor device;
-- doesn't need any auxiliary power supply because it's self-powered
by the voltage to be monitored;
-- impulse-noise immunity is provided;
-- hysteresis is approximately 5-6V;
-- mounted on a standard DIN rail, mounting position is arbitrary;
-- any of three modes of operation can be selected by changeover switch;
-- a wide range of adjustments for each setting:
1) for Umin: 100-(from 5 to 50V);
2) for Umax: 100+(from 5 to 50V);
3) for trip delay: from 0,1 to 10 sec.
-- adjustable setting ranges can be changed, on request;
-- there are two groups independent output contacts (3-4, 5-6): in "dead"
status (the relay is not alive, it's not connected) the 3-4 contacts
are closed and the 5-6 contacts are open;
-- LED indicators for relay status signalling that input voltage is
present and output contacts have changed over;
-- due to digital technology the relay settings are calibrated quite
accurate so they can be set without a control voltmeter.
REV-201
Two-Channel Time Relay
The REV-201 two-channel electronic time delay-on-make relay is designed
to switch alternate 220V/50Hz current electric circuits and direct 24
- 100V current electric circuits with adjustable time delay from 0 to
220 sec. The relay has two channels. Each channel represents the independent
time delay relay. Time delay for each channel begins when voltage is
applied to the channel.
The REV-201 provides three modes of operation:
Mode 1, or the operation mode of two relays. Channels operate independently.
The independent voltage is applied to each channel at different times.
Time delay begins when each channel is energized;
Attention! In the "operating mode 1" power supply of both
channels must use a common neutral.
Mode 2, or the operation mode of one relay with two different delays-on-make.
Channels operate in parallel. One and the same power is applied to each
channel simultaneously. Time delay-on-make for both channels begins
simultaneously. Trip delay corresponds to delays for each channel set
by controls.
Mode 3, or the summing channel operation. Power is applied from one
channel output to another channel input and thus the summation of the
first channel delay and the second channel delay is made.
Also the REV-201 provides the operation mode of periodic load energization/de-energization,
using N.C. contacts in the output of each channel. Power from the first
channel output (pause expiration and load energization) is applied to
the second channel where ON-time begins and when it expires the power
from the first channel is removed by N. C. contact. The relay trips
and restarts the timing cycle again.
The REV-201 has the following features:
-- there are two independent channels;
-- voltage signals are digitalized;
-- the relay power curcuit and output curcuits are conductively isolated;
-- holds-in to the user-specified trip delay with high accuracy;
-- a simple menu setting procedure;
-- the relay accuracy/performance is independent on temperature, humidity
and other ambient parameters;
-- LEDs indicate that time delay begins (power is applied) and that
the relay has tripped;
-- the relay ensures safe operation in the wide range of supply voltage
changes;
-- the relay doesn't need any auxiliary power supply;
-- the relay is practically independent on mains frequency variations;
-- output contacts switch quite a high power;
-- a simple procedure of trip delay setting;
-- different ranges of adjustable trip delay settings are available
at the customer's request;
-- there are two groups of output contacts (one N. C. and one N.O.),
one group for each channel;
-- a low power consumption under load;
-- a long operational life under load;
-- mounted on a standard DIN-rail;
-- compactness and small weight of the relays;
-- high operation reliability and accuracy;
-- the relay can be changed over to the operation of the periodic load
energization/de-energization with the "energization-deenergization"
cycles adjustable by user;
-- parameters are specified by customers additionally.
The REV-201 modifications
1. This modification of the relay is designed for the prestart alarm
system of production equipment including mining-concentrating complexes.
The mode of operation is following: "preliminary signal before
cut-in - pause - signal - installation cut-in".
The relay has two channels. When power is applied to the relay it provides
different operation logic for two output channels.
2. This modification practically replicates the standard REV-201 model
(the front panel is not shown) but provides another time delays for
channels:
1) For the 1st channel it's from 0 to 10 sec;
2) For the 2nd channel it's from 0 to 10 min.
Each channel represents the independent time relay. Time delay for each
channel begins when power is applied to this channel.
3. The present modification provides such mode of operation as "adjustable
time delay-on-power supply (in the 0-10 sec range) - energization
(in the 0-1 sec range) - a wait state -- reset".
The relay has two channels. Each channel represents the independent
time relay. A time delay for each channel begins when power is applied
to the channel. The relay operation cycle is "delay - energization
- the wait state".
PEF-301
UNIVERSAL AUTOMATIC ELECTRONIC PHASE SWITCH
The PEF-301 universal automatic electronic phase switch is a microprocessor-based
single phase unit of automatic throw-over circuit-breaker that performs
monitoring of voltage presence & quality on phases. The switch is
designed to supply an industrial/ appliance single-phase 220V/50Hz load
from three-phase four-wire mains 3x380+N in order to maintain uninterrupted
power supply of essential single-phase loads and protect them against
unallowable voltage variations in the mains. The PEF-301 provides a
simple and correct solution to enhance electric power supply reliability
of single phase loads and to protect them from unallowable voltage variations
in the mains.
Any power load is energized with the interposition of the PEF-301:
-- if power is less than 3,5 kWt (16A), the load is energized from the
PEF-301 directly;
-- if power is more than 3,5 kWt (16A), the PEF-301 controls magnetic
starter single phase coils of the corresponding power.
n Trip threshold for Umin: 160 - 210V
n Trip threshold for Umax: 230 - 280V;
n Reset delay and the initial load energization delay Ton: 1-600
sec;
n Return delay to the priority phase, Tr: 5 - 200 sec range.
The PEF-301 has the following features:
n high trip threshold accuracy is provided;
n a high degree of reliability and accuracy;
n an automatic selection of the optimum phase;
n a high speed of switching is provided;
n monitoring of voltage presence & quality on phases;
n the option of phase priority bringing in/exclusion is available;
n switching to the phase with unallowable parameters is not effected;
n any power load can be energized;
n when sticking of magnetic starter power contacts in external circuit
occurs the switching is disabled;
n starting transient voltage drops ignoring is provided;
n voltage hysteresis exists;
n higher power of output contacts allows in some instances to do without
magnetic starters;
n there are four independent wide-ranged adjustments for basic parameters;
n there are three LEDs that indicate the phase the load is energized
from and the fault-indicating LED;
n due to digital technology the relay trip settings are adjusted quite
accurate and so one doesn't need to read voltage on the control
voltmeter;
n a procedure of trip thresholds setting is very simple;
n a wide range of operating temperatures is provided;
n mounted on a standard DIN-rail;
n low power demand;
n small dimensions and small weight of the relay.
UBZ-301
Universal Induction Motor Protection Unit
The UBZ-301 universal electromotor protection unit belongs to the new
generation of electromotor protection devices. Application of modern
microprocessor-based technology allows to use the necessary unit operation
logic that no protection devices of domestic and foreign production
can provide. The UBZ-301 is a conceptually new reasonably-priced device
that provides full and effective multi-fault protection (protection
from all faults in the mains, motor performance-induced faults and internal
fault conditions of motor) for 3-Phase AC motors by a magnetic starter
(contactor) coil control. The unit is designed for the continuous monitoring
of the mains voltage parameters and for RMS phase/line currents of 3-Phase
AC 380V/50Hz electrical equipment monitoring, primarily, of induction
motors that develop power from 2.5kWT up to 315 kWt, isolated neutral
system included. It offers a solution for an electric motor heat balance
equation.
There are three separate modifications of the UBZ that cover three nominal
current ranges:
UBZ-301 5-50A;
UBZ-301 10-100A;
UBZ-301 63-630A.
The unit isolates electrical equipment from the running system and/or
disables its start:
n when the mains voltage is of poor quality (unallowable voltage jumps,
phase loss, incorrect phase sequence and phase "coincidence",
phase/line voltage imbalance);
n when mechanical overloads (symmetrical phase/line current overload)
take place. The unit performs overload protection with a dependent time
delay;
n when phase/line current asymmetrical overloads induced by faults inside
the motor occur. The unit performs protection from phase current imbalance
and further disables an automatic reset;
n when phase current asymmetry without overload occurs that is induced
by the insulation fault inside the motor and/or the power cable;
n when motor load is lost ("dry stroke" for pumps). The
unit provides the minimum start and/or operating current protection;
n when insulation level to frame is abnormally low. The unit performs
insulation level test before start and if the insulation is poor the
start is disabled.
n when stator winding ground-to-fault occurs during operation. The unit
performs the ground leakage current protection.
THE UBZ-301 PROVIDES:
n a simple and accurate electromotor nominal current setting by nominal
current standard scale;
n the electromotor operating current setting that differs from standard
values;
n overload tripping with a dependent time delay (the current-time characteristic
curve is plotted for a conventionally cold motor). The motor heat balance
differential equation is being solved in the operation process. This
approach enables to take account of the preceding electromotor status
and to make a decision on heat overload presence with the maximum validity.
This method also permits to allow for a motor start heating and to restrict
(at the customer's option) amount of starts per unit time;
n shift of current-time characteristic curve along the current-axis
and along time-axis as well;
n setting of trip thresholds for the minimum/the maximum voltage, line
voltage & phase current imbalance, and also for automatic reset
delay at the personal customer's discretion;
n fault type indication, the mains voltage presence indication, current
range indication the unit is adjusted to, and load energization indication;
n the data exchange and transfer to the local computer network according
to the RS-485 MODBUS record through the BO-01 exchange unit (BO-01 is
supplied on order).
The UBZ-301 has the following features:
n the unit is a microprocessor-based digital device;
n a high degree of reliability and accuracy is provided;
n the unit doesn't need any auxiliary supply because it retrieves
it's energy demand out of the measurement signal: it's self-powered
by the voltage to be monitored;
n simultaneous isolated independent monitoring for the mains voltage
and phase currents permits to detect the type of occurring fault and
to provide a different decision-making logic for each fault type;
n when the mains voltage faults occur the unit performs automatic load
reset on return voltage parameters to normal operating conditions;
n if a fault is induced by abnormal condition inside the motor (phase
current imbalance at the symmetrical power line voltage, leakage current
presence etc.) restart is disabled;
n when the unit trips, the load is de-energized by a break in the magnetic
starter coil power circuit;
n nominal parameters and trip thresholds are set by front-panel screwdriver
potentiometers;
n the unit provides an insulation level monitoring;
n when phase current imbalance (in %) is twice exceeds voltage imbalance
the automatic reset is forbidden and the unit is disabled;
n nominal currents setting is to be performed correcting for load connections
(Wye/Delta), 'cause currents are measured by toroidal current
transducers which are put on the load power leads. When the load connection
is Wye, the currents correspond to the load phase currents. When load
connection is Delta, the load phase currents are 1.73 times less than
the currents that flow through power leads;
n the motor is protected from the heat overload; after the load has
been de-energized owing to the heat overload it will automatically be
energized again:
a) according to a heat hysteresis if time delay Ton=0, i. e. the motor
must cool down 30% of the stored up heat;
b) according time delay Ton if Ton>0;
n by suitable selection of different Ton values, heat hysteresis considered,
one can reduce number of starts per time unit because in the intermittent
cycle the unit stores heat quantity released at the start of the motor;
n the unit produced is completely ready for operation and needs no special
pre-starting procedure measures;
n owing to digital technology all the unit settings are aligned quite
accurate, so no control devices are needed to adjust them.
The NOVATEK-ELECTRO company constantly modernizes output products, enhancing their consumptive quality as well as develops new competitive articles. The company's activity is based on the concepts of reliability, high quality and law cost that are provided by the application of the latest achievements in modern knowledge-intensive digital microprocessor-controlled technologies.
Our products are mounted and assembled on the modern equipment and incorporate the high electronic mounting technologies. Experienced developers and programmers of the company make good use of the cutting-edge software products. The strategy of our company is to provide consumers with the reliable and high-quality devices not second to the foreign analogues. The assembly production is in Saint-Petersburg - the town which is famous for the high level of the professional culture.
One of the main lines of the NOVATEK company's activity is readiness for joint projects. Different collaboration types are available. For instance, we can develop and manufacture the products that the Customer is interested in. If a project is of interest to us we also can develop a product independently at our own expense. We can develop products profiting from the customer's expenses. Organization of a joint production and/or marketing in other countries can be another aspect of cooperation. We are of the opinion that this kind of cooperation can evolve gradually. The first stage involves establishing a market for the sale of the devices we produce. The next stage includes the assemblage of large units at your place. The last stage is the organization of integrated production that implies the transfer of all essential technology.
Among the short-range plans of our company is to bring to a commercial
level a production of such devices as:
-- single-phase/three-phase mains voltage stabilizers with built-in
voltage protection functions;
-- universal power supplies with the rigorously sinusoidal any-frequency
output voltage;
-- gradual start devices, induction motor speed governors;
-- rectifier units and chargers, etc.
Our address:
Of.137, 21 Kondratievsky Prospekt, St-Petersburg, 195197, Russia
Tel: +7 901 300 48 46, +7 812 740 77 38
Fax: +7 812 740 74 55