Electromechanical Bypass (E...
5.1.4 EMB2 Run Permissive
General Information
Run permissive allows a remote signal to notify the drive to start, indicating the system is safe to operate. Run permissive works in drive or bypass mode. Run permissive is enabled by factory default and can be disabled by switching dip switch #4 on S105 to the on position or placing a jumper wire between terminal 1 and 2 of the X55 customer connector.
Prior to Enabling Run Permissive
•Complete the
•Verify that the drive is programmed for the run permissive function. See the drive support manual provided for information on programming the run permissive function.
Operation
•A start command can be from local hand start on the drive keypad or a remote auto start signal through digital input connector X55 terminals 3 and 4, or via the serial communications input.
•In response to a start command, an output request is sent from X55 terminals 11 and 12 to the external equipment (to activate a valve or damper, for example).
•When a return run signal on X55 terminals 1 and 2 is received, the motor is started in either drive or bypass mode, depending upon the bypass switch position.
Run Permissive Function Setup
•Remove the
•Wire the output run request to connector X55, terminals 11 and 12.
•Wire the input run permission to connector X55, terminals 1 and 2 per the system application.
Disable Run Permissive
•Run permissive is enabled by factory default when ordered.
•To disable the run permissive function, jumper between terminals 1 and 2 on connector X55 or use dip switch 4 on 5105.
5.1.5 EMB2 Overload
General Information
The overload device provides overcurrent protection for the motor when running in bypass. The thermally activated overload monitors motor current and trips to remove power to the motor if a sustained
Prior to Enabling Overload
•Verify that the overload current dial setting matches the motor FLA rating on the motor nameplate.
•If the motor FLA is greater or less than the range of the current dial, reconfirm that the motor hp and voltage are within the option panel (and drive) rating. If greater than the FLA rating, replace the panel with one of a proper rating.
CAUTION
MOTOR DAMAGE!
Repeated attempts to reset an overload can cause motor damage. Correct the overload condition and let the overload and motor return to normal operating temperature before resetting. See motor manufacturer’s recommendations for time between start attempts. Failure to correct the overload condition and let the motor return to normal operating temperature could cause motor damage.
Operation
Overloads are rated by class. The class is defined by the NEC to determine the maximum time to trip. A Class 20 overload, for example, has a typical trip delay of 20 sec. or less at 600% current and normal operating temperature. This allows for high motor inrush current for 20 sec. while the motor is ramping up to synchronous speed. The trip time, however, is based on the percentage of overload. The higher the overload, the shorter the trip time. It is important that the overload class not exceed the motor class rating or motor damage could occur.
Overload Function Setup
•Set the overload current dial to the FLA of the motor. DO NOT add the service factor of the motor into the setting. A service factor of 120% for Class 20 is designed into the overload.
•Pressing the test pushbutton verifies the operation of the overload. The overload should
