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fancypants
12-28-2015, 11:02 AM
My pump used for mash/wort transfer seems to be "weakening". As in, when I transfer a mash at say 90volts, usually a relatively quick speed, it doesn't want to keep up. Is this an electrical issue or something mechanical within the pump? My mash transfers went from 10-15 to 25-30.

J.Scholb
12-28-2015, 12:03 PM
That could be a variety of problems. Do you have a clamp on amp meter (Harbor Freight has a cheap one)? Check the amp draw. I assume you have a VFD since you can run it down at 90 volts. Is the motor getting hot from running at this low voltage?

Things that could be causing the problem:
Motor windings are going bad creating more heat and less power for turning the shaft
VFD could be going bad, not supplying the right amps at the needed voltage
The pump could be plugged or seals going bad, causing more friction

Check the amp draw and voltage. Open the pump housing to see if there is plugging. See if the shaft can be turned and if there is a lot of friction.

TGTimm
12-29-2015, 08:51 AM
The first thing I'd check is the electrical connections in the electrical box on the pump. These are usually hooked-up with wire nuts, and are very prone to loosening and corrosion. Be sure to disconnect/lockout the electrical supply first. If this doesn't solve your problem, check and tighten all other electrical connections from the breaker all the way to the pump. Screw-clamp connections loosen over time due to heating/cooling cycles. Once a connection gets a little loose, it generates heat and quickly gets worse.