Replacing a stepper motor on a Waters 2695 pump

[jbozell]

Hello everyone,

In discussion with Waters regarding our 2695 HPLC system, they have diagnosed a bad stepper motor on the back of one of the pumps. Waters does not sell replacement motors separately, but the motor appears to be attached to the pump by a set of screws. We would like to know if the motor can simply be swapped out with a new one, as Waters only solution is to purchase the entire pump/motor module.

thanks!

Joe in Tennessee

[uzman]

It may be the same step motor used Waters 510 model pumps .
You may buy a 510 pump from ebay around $100 , it is worth to try.

[jbozell]

@uzman: thanks much for the hint. The motor is a Powermatic II which is also available on line, ebay, etc. What I'm wondering is whether there are any particular challenges to removing an old motor and replacing it with a new. If we unscrew the motor, will we damage any seals or specific alignments, etc.? Or is it as simple as pulling off the old motor and replacing it with a new one?

thanks!!

Joe in Tennessee

[uzman]

Hi Jo ,

I don't think that you will damage something by removing the motor.
Motors are easily replaceable parts ( especially step motors ) , four screws fixing them from their corners.

Most probably , there is a toothed wheel on the motor spindle , which you may transfer it to the new motor if the new motor doesn't have one.

The more important point is , you must connect the cables correctly , if the motor sockets are not the same configuration , otherwise the motor may turn in the reverse direction.