Description - Siemens SIMOVERT Masterdrives SSB Operating Instructions Manual

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Description

The SSB board is designed for SIMOVERT MASTERDRIVES, types ≥ E.
The SSB board guarantees that a rotating field will not be produced in the connected motor when the "Safety
Off" function is active . To realize this, a safety relay on the SSB board switches-out the power supply of the
coupling elements (optocoupler, fiber-optic cable) between the control electronics and power section.
If the power supply is shutdown via the safety
relay, the power section can no longer power the
connected motor, even if the control electronics
(microprocessor) outputs firing commands. In this
status, the drive is in a "safety off" condition, even
if there is no electrical isolation between the motor
and converter and none between SIMOVERT
MASTERDRIVES and the line supply.
The safety relay has two contacts, an NO and an
NC contact, which are mechanically connected so
that the NC and NO contacts cannot be
simultaneously closed, even when a faulty
condition develops (e.g. when the contacts are
welded together). The NO contact connects the
coupling elements with the power supply and the
NC contact is used to output a checkback signal.
For example, this signal can be used to control a
signal lamp which indicates the "safety off" status.
In the "safety off" status, the SSB board prevents the motor accidentally rotating.
However, even in the "safety off" status, the motor terminals are at a hazardous potential!
The SSB board is not suitable to decelerate a motor as quickly as possible down to standstill. When the gating
signals are disabled, the motor is only braked by the connected load!
The motor should be decelerated down to standstill using SIMOVERT MASTERDRIVES and then be brought
into the "safety off" status using the SSB board. Mechanical work can then be carried-out on the drive, when
the line supply voltage is still connected and there is no electrical isolation between the motor and SIMOVERT
MASTERDRIVES.
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Coupling elem ent
power supply
Safety relay
Fig. 1-1 Integrating the safety relay into the SIMOVERT
MASTERDRIVES gating circuitry to implement the "safety
off" function
NOTE
Checkback signal
Power section
gating
Siemens AG 6SE7080-0AX87-1JB0
Safe Stop Board Operating Instructions
02.2000