ZSA 2-phase

One phase is located directly on the motor; both others are controlled. These devices create very good motor soft start up with selectable start up time and initial voltage. Additionally these devices produce a soft start up with separately selectable slow down time.

Even though one phase is consistently at the motor in case of these devices, the current can flow only when both other phases are increased. By doing this it is possible to switch the motors using an electronic via an N/O contactor or with SPS. The semiconductors are also switched dead in case of these devices using two internal bypass relays or an external contactor. One phase is always at the motor. The start up current is little higher in the non controlled phase. This principle is in accordance with the ZSA (Zweiphasen-Sanftanlauf/Two phases- Soft start up device).

The ZSA-Devices have an excellent acceleration behaviors in case of simultaneous Startup-current limiting. Hence these are also suitable for all the normal start up behaviors with various loads. These can be switched electronically using contacts and also using the operational voltage. Considerable higher switching frequencies are realized than in case of ESA. The ramp voltage is always identical with the current output voltage. Thus a trouble free Inching-Operation is possible.