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Microprocessor Motor Protection Relays of 0,4 kV
RDC-01-055, RDC-01-205


RDC-01-055, RDC-01-205 - microprocessor motor protection relays
RDC-01-055

Motor protection relays RDC-01-055, RDC-01-205 (with digital control and indication of controlled parameters) are intended for protection of three-phase asynchronous electric motors of 3х380 V 50 Hz with direct connection by the power (0,55...2,2) kW (RDC-01-055), (2,2...9,0) kW (RDC-01-205) and with connection via measuring transformers of current with the power (9,0...450) kW (RDC-01-055).

The relays RDC-01-055, RDC-01-205 protect from the following situations:

  • Current overload;
  • Rotor blocking;
  • Loading asymmetry;
  • Underrunning;
  • Excess of supply voltage;
  • Reduction of supply voltage;
  • Short circuit (current cutoff);
  • Reverse phase rotation;
  • Reduction of insulation resistance of motor coils before start-up.

The relay carries out switching of electric circuits when the controlled parameters will be equal to previously programmed levels.

The relay has an opportunity to turn off the action of the following functions:

  • Protection against maximum voltage;
  • Protection against minimum voltage;
  • Protection for off-load/dry course;
  • Protection against current asymmetry;
  • Current cutoff;
  • Protection for rotor blocking;
  • Protection against wrong phase rotation;
  • Protection of insulation resistance.

The relays can work in one of two modes:

  • Current checking in phases: А, В and С;
  • Current checking in phases: А and С.

At the same time (except protective functions) the relays have a possibility of monitoring:

  • Current consumption for each phase (IA, IB, IC or IA, IC);
  • Network voltage for each phase (UA, UB, UC);
  • Insulation resistance before motor start-up;
  • Network frequency;
  • Motor term of life.

The relays are manufactured:
- in climatic modifications U of category 3 (for deliveries to areas with a temperate and frigid climate);
- in climatic modifications T of category 3 (for deliveries (export) to areas with tropical climate).

Габаритные размеры реле: 140х70х137 мм.


SUZD - the stations of control of electric motors
SUZD - the stations of control of electric motors



At the enterprise on the basis of the protection devices of the RDC series the stations of control of electric motors are produced. These stations are intended for work with the three-phase asynchronous motors 550 W – 350 kW of various producers. The stations are made according to various schemes with a possibility of a full complete set of electric equipment and are intended for automatic and manual control, automation, scheduling and also in various systems of water supply where asynchronous motors are used. The stations automatically support the set pressure in the system of water supply or the set level in the tank, provide complex protection of the electric motor against emergency operation. Learn more...







Main technical characteristics of the relays RDC-01-055, RDC-01-205

Measuring current circuits of the RDС-01-055 relay are used for direct switching-on in network or in external measuring transformers of current (secondary current - up to 5 A; the recommended accuracy class - 0,5; transformation coefficient - in the range (5/5...1000/5)). Measuring current circuits of the RDC-01-205 relay are used for direct switching-on in network (rated current - to 20 A).

Characteristics of the devices RDC-01-055 RDC-01-205
Rated three-phase (phase/linear) supply voltages Uph.rated / Ul.rated, rated frequency 50 Hz 1-500
Limits of permissible deviations of supply voltages concerning rated one:
- upper limit
- lower limit

+30% от Urated
-35% от Urated
Rated input current of internal current transformers for each phase (1…5) А (5…20) А
Measurement range of current by internal current transformers for each phase (0,2…50) А (0,8…200) А
Average main error of voltage measurement ± 2,5 %
Average main error of current measurement:
- in the ranges: (0,2…1) А for RDC-01-055; (0,8…5) А for RDC-01-205
- in the ranges: (1…30) А for RDC-01-055; (5…120) А for RDC-01-205
- over 30 А for RDC-01-055; over 120 А for RDC-01-205

± 0,1 А
± 2,5 %
± 10 %

± 0,4 А
± 2,5 %
± 10 %
Measurement range of the network frequency (49,5…50,5) Hz
Error of the frequency measurement ±0,1 Hz
Number of decimal places of the indicator 4
1 decimal place – mode
3 decimal places - value
Number of LED indicators:
K      status indicator of output relay
I >     indicator of current overloading
I ≠     indicator of current asymmetry
I <     off-load indicator
U >    indicator of voltage excess
U <    indicator of voltage decrease
ABC   indicator of wrong phase rotation
Rиз < indicator of insulation resistance reduction
8
+
+
+
+
+
+
+
+
Settings of protection actuation limits:
- rated phase supply voltage Urated
- setting of maximum voltage Umax
- setting of minimum voltage Umin

АС 220 V, 50 Hz
(110…125)%•Urated   /OFF
(70…95)%•Urated   /OFF
- Setting of transformation ratio of external current transformer of the phases фаз, КТf (RDC-01-055)
- Setting of rated current of the motor Irated
(1…200)
(1…990) А
-
(5…20) А
- Setting of actuation limit for rotor blocking
- Setting of current cutoff level
- Setting of actuation limit of element of: off-load/dry course, Iхх
- Setting of asymmetry of the loading current Iasym
(1,1…6,0)•Iном   /OFF
(6,0…10,0)•Irated   /OFF
(20…85)%•Irated   /OFF
(20…55)%•Ioperating   /OFF
- Setting of start-up time of electric motor, tstart-up
- Setting of actuation delay for for rotor blocking tblocking
- Setting of time delay for inversely dependent time-current characteristics Тsetting
- Setting of actuation delay of element of off-load/dry course tdelay.xx
- Setting of actuation delay of voltage element (Umax, Umin), tdelay.v
- Setting of actuation delay of current element (Iasym, phase break), tdelay.c
- Setting of a number of automatic repeated start-ups after emergency shutdown for current
- Delay setting of automatic repeated start-ups after emergency shutdown for current
- Delay of current cutoff
(1…99) с
(0,1…30,0) sec
(0,1…20,0) sec
(0,1…30) min
(1…255) sec
(1…255) sec
(0…5)
(1…999) sec
(50…100) msec
- Actuation setting for insulation resistance reduction before the start-up of the electric motor
- Average main error of insulation resistance measurement before the start-up of the electric motor
(0,3…3,0) МОm/off

± 10 %
Switching capacity in the circuits of alternating current АС-22 about 250 VА
Mechanical durability and electrical endurance of the relay not less 500 000 cycles
Type and a number of relay contacts 1 make contact
Operable time not more than 2 s
Power consumption in the range of the supply voltages not more than 9 VА
Outside and linkage dimensions of the relay 85х140х137 mm
Weight of the relay not more than 0,7 kg

Main parameters and technical characteristics

The relay shouldn't have false operations (actuations of the make contact) at short-term voltages dips and surges of voltage during the time not more than 50 ms.


Scheme of external connections of the relays RDC-01-055, RDC-01-205


                     1 - connection terminal of measurement circuit of insulation resistance;
       2 - contact terminal of execution relay;
       3…6 - connection terminals of three-phase network (UA, UB, UC, UN);
       7-8 - connection terminals of circuit IА;
       9-10 - connection terminals of circuit IB;
       11-12 - connection terminals of circuit IС.

The relays RDC-01-055, RDC-01-205 can work in one of two modes:

  • Current checking in the phases А, B and С;
  • Current checking in the phases А and С.


Connection scheme of the relays RDC-01-055, RDC-01-205 for the phase current checking mode (A, B, C)

a) b)

                     FU – protective devices;
                     К – electromagnetic starter (at the connection scheme - 380 V);
                     S1 – button of turning-on of motor;
                     S2 – switcher “automatic/hand work (A/P)“;
                     S3 – button of turning-off of motor;
                     ТА – external measuring transformers.

                     а) Connection scheme of the relay RDC-01-055 through external measuring transformers.
                     b) Connection scheme of the relay RDC-01-205 and direct connection of the relay RDC-01-055.

Relay connection to single-phase supply voltage is allowed in the case of the turned-off control of phase rotation (UN - terminal 3, UA – terminals 4, 5, 6).


Connection scheme of the relays RDC-01-055, RDC-01-205 for the phase current checking mode (A and C)

a) b)

                     FU – protective devices;
                     К – electromagnetic starter (at the connection scheme - 380 V);
                     S1 – button of turning-on of motor;
                     S2 – switcher “automatic/hand work (A/P)“;
                     S3 – button of turning-off of motor;
                     ТА – external measuring transformers.

                     а) Connection scheme of the relay RDC-01-055 through external measuring transformers for the phase current checking mode (A and C).
                     b) Connection scheme of the relay RDC-01-205 and direct connection of the relay RDC-01-055 for the phase current checking mode (A and C).

Relay connection to single-phase supply voltage is allowed in the case of the turned-off control of phase rotation (UN - terminal 3, UA – terminals 4, 5, 6).

Attention! At the mounting it must be kept in mind that the contact of the output relay (terminals "2", "4") has galvanic communication with the supply chain (terminal 4, phase A on voltage).


At the request of the customer the devices can be presented with current transformers of the following ranges:

Range of current transformers, А
20-50
40-100
80-200
160-400
240-600

Outside and linkage dimensions of the relay RDC-01
Outside and linkage dimensions of the relay RDC-01