RN-112
Universal electronic maximum minimum voltage relay

APPLICATIONS

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:

• the minimum voltage relay mode (the relay trips only when the minimum voltage threshold is reached);
• the maximum voltage relay mode (the relay trips only when the maximum voltage threshold is reached);
• the symmetry settings mode (the relay trips when both the maximum and the minimum voltage thresholds are reached).

Fig.1 The RN-112 front panel with controls description.

1 – control for trip voltage setting,Umean=100±ΔU,

2 – control for changeover switch,

3 – control for trip delay setting.Toff,

4 – green LED indicating that input voltage is present,Uin;

5 - green LED indicating that output contacts have changed over,Output;

6 – input contacts,

7 – output contacts.

DESCRIPTION

The relay is a digital microprocessor device. The relay doesn't call for an auxiliary power supply because it's self-powered by the voltage to be monitored. The relay is connected in parallel to the mains supply to be monitored by the (1-1) - (2-2) input contacts. For the ease of wiring the input contacts are provided with twin terminals, i. e. the 1-1 terminals are the first point of connection and the 2-2 terminals are the second point of connection . The relay has two groups of independent output contacts (3-4, 5-6). In the "dead" status (a voltage is not applied to the relay or the relay is not connected) the3-4 contacts areclosed and the5-6 contacts areopen.

The 3-4, 5-6 output contacts specification

The long-term tolerable current through the closed contacts is no less than 5A. The relay is impulse-noise resistant. The rated operating value of mechanical factors at work corresponds to the mechanical construction group. During vibration-resistance tests of the relay the following test parameters are set:

• a frequency range - 10-80 Hz;
• an acceleration amplitude - 50 msec ( 5.0 g )

The tests are carried out under load. The relay is mounted on a standard DIN-rail, the mounting position is arbitrary.

Operation in the minimum voltage mode

When a nominal voltage is applied to the relay input, the relay is brought for the service availability after the readiness delay Tr=0,3--0,4 sec has expired : the N. O. 5,6 contacts close and the N. C. 3,4 contacts open. If the input voltage reaches/drops below the minimum voltage threshold the relay trips after the adjustable trip delay Toff that varies in the 0.1 - 10 sec range has expired. When the voltage drops below 40V, the relay is accelerated to trip with the trip delay Ta=0,1 sec despite the user-preset trip delay Toff. On return to normal operating conditions when the voltage to be monitored reaches the level set by hysteresis (5-6V), the relay will reset automatically after the readiness delay Tr has expired: the 5, 6 contacts close and the 3,4 contacts open. If the input voltage was always applied to the relay or was removed just for a moment, the readiness delay Tr is no more than 0.1 sec. If the voltage applied to the relay input is below the set trip threshold for voltage, the contacts keep the "dead" status positions: the 5, 6 contacts remain open and the 3,4 contacts remain closed. If the input voltage exists, the green "Uin"; LED is always on, but if the input voltage drops below 20V this LED is going out gradually and at 5V the LED switch off. The green "Output"; LED switches on when the 5,6 contacts close and the 3,4 contacts open.

The maximum voltage mode of operation

When the nominal voltage is applied to the relay input, the contacts keep the position corresponding to the dead status of the relay, i. e. the 5,6 contacts remain open, the 3, 4 contacts remain closed; the green "Uin" LED is ON, the green "Output" LED is OFF. When the input voltage reaches the maximum voltage threshold, the relay trips with the adjustable trip delay Toff (0.1 -10 sec): the 3,4 contacts open and the 5,6 contacts close. On return to normal operating conditions when the input voltage drops below the maximum voltage threshold, reaching the level set by the hysteresis (5-6V), the relay will reset automatically after Tr=0.1 sec has expired: the 3,4 contacts close and the 5,6 contacts open; the green "Output" LED switches off. When the input voltage keeps stepping down the positions of the relay contacts remain unchanged. If the voltage drops below 20V the green "Uin" LED goes out gradually.

Operation in the symmetry settings mode

When a voltage applied to the relay input is within the maximum and the minimum voltage settings, the relay is brought for the service availability after the readiness delay Tr=0,3 - 0,4 sec has expired: the 5, 6 contacts close and the 3, 4 contacts open.

If the voltage level drops below the minimum threshold/exceeds the maximum threshold the relay trips when the adjustable trip delay Toff has expired: the 5,6 contacts open and the 3,4 contacts close. On return to normal operating conditions when the voltage regenerates reaching the level set by hysteresis, the relay will reset automatically after Tr=0.1 sec has expired: the 5,6 contacts close and the 3,4 contacts open. If the voltage drops below 40V the relay is accelerated to trip with trip delay Ta=0.1 sec.

Um - voltage to be monitored;

Ut - adjustable trip threshold (level) for voltage;

K3,4 - the 3, 4 output contacts;

K5,6 - the 5.6 output contacts;

Toff - adjustable trip delay (0.1 - 10 sec);

Ta - accelerated trip delay (trip delay removal) in the minimum voltage threshold mode of operation and in the symmetry setting mode of operation when Um drops below 40V (Ta ≤ 0.2sec);

Tr - readiness delay and reset delay

(*) on return to normal voltage level (Tr ≤ 0.2 sec);

LEDin - LED of input voltage;

LEDout - LED indicating that output contacts have switched.

It's recommended to adjust trip settings and the mode of operationin the "dead" status of the relay. In testing mode it's allowed to adjust settings under voltage, following safety regulations.

TECHNICAL BRIEF

PRELIMINARY STARTING PROCEDURE AND SERVICE MANUAL

The relay produced is ready for use and doesn't require special preliminary procedure measures. Due to digital technology trip settings of the relay are calibrated quite accurate so they can be set without a control voltmeter. To install the relay at the using activity after extended storage it's recommended to test functionality of the relay. Application of the relay according to specifications above and to the present certificate during service life, continuous work included, needs no preventive maintenance.

Setting of trip values and selection of the relay mode of operation is given below (the order of operations is arbitrary):

1. To set trip threshold (% of nominal voltage) by control 1 (see fig. 1).

2. To set the relay mode of operation by control 2 (see fig. 1). In the "min" position the relay operates in the minimum voltage relay mode, in the "max" position the relay operates in the maximum voltage relay mode, in the position "min/max" the relay operates in the symmetry voltage thresholds mode, i. e. the relay trips when the voltage to be monitored drops below/ exceeds the voltage threshold set by control 1. Areas of the modes are described by full arc.

3. To set trip delay by control 3 (see fig.1) if necessary.

It's recommended to set trip thresholds and the mode of operation in the "dead" status of the relay. It's admissible to set trip thresholds under voltage in a testing mode following safety regulations.

Adjustable setting ranges can be changed at the customer's request.

WIRING DIAGRAM