There are two common reasons why a P Drive would fail to enable its power stage when commanded without throwing an error. In both of these cases, the user should see that the Servo Ready LED is off.
The two common drive enable issues and how to fix them:
Incorrect voltage setting. If the drive is being operated at 110VAC (either single or three-phase), it needs to be configured to run at that voltage. See this FAQ about configuring a P Drive to run at 110VAC.
NOTE: Only the PD-04P and PD-04C can be run at 110VAC. All other P Series drives must be run at 230VAC.
Jumpers are missing. Check the front of the drive for the presence of the factory-installed jumpers from P0 to PI and B to BI.
It is also possible to connect P0 and PI to a DC line reactor. See the this FAQ for additional information.
The jumper from B to BI is there to let the drive use its internal braking resistor. Some users may need to use a larger external braking resistor if their application produces a large amount of braking energy. In this case, an external braking resistor should be connected to B and B+ (BI should not be connected).
NOTE: There are additional parameters that need to be set in the drive when adding or removing an external braking resistor. Failing to change these parameters can damage equipment.
UPDATED 23JAN2017 DC