ABB ACS 502 Series, Installation & Start-Up Manual

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Chapter 2 – Overview of the ACS 502/504
ACS 502 Installation & Start-up Manual 2-19
Manual Bypass with
Service Switch
The Manual Bypass with Service Switch option is the same as the Manual
Bypass option with the addition of another switch, and a third (input)
contactor on the line power side of the drive. The additional switch allows you
to apply power to, or remove power from the drive for servicing while the
motor continues to operate on line power. In the BYPASS position, the Drive
Input contactor opens and removes power from the drive. The Drive Input
contactor is also controlled by the three position Service Switch, with the
positions labeled NORMAL, OFF, and TEST. This switch is mounted inside
the enclosure. In the NORMAL position, the Bypass switch controls the Drive
Input contactor. In the TEST position, the Drive Input contactor is closed. In
the OFF position, the Drive Input contactor is open.
Note: The Drive Input contactor opens when BYPASS is selected, removing
power from the drive. The service switch will energize the input
contactor in the TEST position to allow the drive to be powered while
in BYPASS for servicing.
Note: The ACS 502 is disabled when BYPASS is selected. If the drive is to be
run while in BYPASS, a connection must be made between TB1:42 and
TB1:43. This should be done by a qualified service technician only.
CAUTION: Return the service switch to Normal and remove the jumper
from TB1:42 to TB1:43 before switching from BYPASS to NORMAL.
Failure to do so could result in damage to the ACS 502.
Note: The Output contactor opens when the drive receives a stop command,
which will cause the motor to coast to a stop. If ramp to a stop is
required by the application, it will be necessary to install wires from
TB1:25 to TB1:40 and from TB1:26 to TB1:41. This will cause the
Output contactor to remain closed until the output frequency reaches
0 Hz when a stop command is received.
CAUTION: If BYPASS is selected, and the motor is not running because a
stop command is given, the motor will start when the drive is started.