Automatic star-delta switch / star-delta time relay

Relay for star-delta starting modes (ERV-YU)

The ERV-YU starting relay is designed for automatic control of starting electric motors in the STAR-DRINAGON mode with an operating voltage of 24/220 V AC . The relay ensures a soft start of the motor, reduces the starting current and extends the service life of the entire drive system. It is equipped with light indication of the ON , STAR , TRIANGLE modes and allows you to set the start time.

Description and operating principle

To ensure a soft start of the electric motor, the STAR mode is first activated, which reduces the initial current surge. When the desired speed is reached, the coil automatically switches to TRIPLE mode, in which the motor continues to operate in normal mode.

Automatic mode switching by relays and contactors increases the stability of the entire system and eliminates the risks associated with manual operation.

When voltage is applied to the relay terminals A1-A2 :

• The STAR contact is activated, the STAR indicator lights up and the t1 start interval (0.1-30 s) starts counting.

• After the time t1 has elapsed, the STAR contact is broken, the indicator goes out and a short pause t2 (15 ms ) begins.

• After that, the PHASE-TRIANGLE contacts are turned on, the TRIANGLE indicator light comes on, and the relay remains in this mode as long as voltage is applied to terminals A1-A2 .

Use

The ERV-YU relay is suitable for:

• automatic control of motors in star-delta mode

• Industrial applications where stable and safe starting of motors places high demands on stable and safe starting.

• for systems where starting current needs to be reduced and the electrical network needs to be protected.

Additional range

You can purchase the following for the relay:

• Contactors and starters

• mechanical interlocking contactors

• independent mechanical locking modules

• IP65 metal housings

All this directly from stock, at a competitive price.