AOIP-Electrolytic starters for low and medium power cage synchronous motors (Model:RED)

Reliability

• They do not have any moving parts other than the short circuit contactor
• There is no current peak at the end of the starting period

Economy

• Electrical and mechanical maintenance considerably reduced
• Units pre-wired

Adaptability

• The starting characteristics are “made to measure” and can be altered for a change of motor or machine by simply replacing the electrolyte.

Description

The starters of this range can be supplied in three formats: RC, RW or RZ. They are made up of two parts:

• The electrolytic starting resistance in a frame with tanks and a thermostat.
• The equipment:
  • An enclosure integrated into the frame which contains a short circuit contactor, a timing relay, eventually a line contactor or further option. The RC and RW units are supplied in this format.
  • A separate WS wall mounting enclosure can be used with RZ frames. The RZ/WS modular assemblies are prewired.

Operating principle

The decrease in resistance of an electrolyte when heated is used inside an electrode chamber. The resistance is connected in series with the motor windings to reduce terminal volts, starting torque and current drawn from the line.

As the motor runs up to speed, there is an automatic decrease in resistance value with a consequent increase in motor voltage, giving smooth acceleration without torque or current peaks.

At the end of the run-up period a timed contactor closes and short circuits the residual resistance.

Reduction of the starting torque is determined according to the requirements of the driven machine or the current limitation.

Electrical features:

Voltage between phases: 690 V

* In case the starter is made of more than one enclosure, only one has a thermostat.

The RC or RW enclosure consists of the starting electrolytic resistance and the short-circuit start and run contactor with relay timer.
The resistance frame RZ consists of the resistance only with a thermostat*, and can be delivered with separate waterproof enclosure WS for chemical industries and for marine environments (see below).
The WS3 enclosure has been designed to accept equipment which cannot be mounted in RC and RW enclosures and when the starter is supplied with RZ type resistance frames.

Further features