PM1030-V Spindle speed anomalies

[Red96]

Was wondering if any other PM users have/are experiencing this. My lathe spindle speed will drop 100-200 rpm for no apparent reason for a few seconds and then return to the set spindle speed. Bearings are not getting hot, no apparent drag in the geartrain. This started about a month ago - speed dropped while machine was running freely, then returned to normal speed. I noticed it only due to the change in tone, and thought to myself 'That was weird'. Didn't do it again for a few days. Now it is happening more and more frequently, so I'm starting to get a bit concerned.

I've sent an inquiry about the issue to PM, but thought I'd throw it out here, as I said above, just in case somebody else has noticed something similar or it is a known issue. Will follow up on here when I hear back from PM.

 

[Reddinr]

I wonder if it is the speed potentiometer? Dirty, corroded or worn? In any case I bet it is on the "analog side" of things, not the microprocessor's digital side or motor driver side. Is there a procedure for making sure that the RPM sensor is aligned and spaced properly? Is there an RPM sensor? I don't know that machine in particular.

 

[Red96]

Just got a reply from PM, and they also suggested looking at the speed pot for potential loose wires or carbon on the winding. Thanks for the reply.

 

[markba633csi]

Unplug and plug the pot connector a few times to clean off any corrosion.
You could also drip some lighter fluid into the pot, exercise it a bit and let it evaporate
Solder joints sometimes break at board connector header pins. Reflow as necessary
Next step would be replacing the pot, followed by the circuit board, then the motor
Isn't electronics fun?

 

[epanzella]

Start with "wiping the pot". Run the pot all the way up and down a dozen times with the machine off.

 

[Red96]

Thanks for all the suggestions. Currently enjoying a fresh dose of Covid, but I'm hoping to get back in the shop this coming weekend.

Using my abundance of free time this week to try to wrap my head around FreeCad.

 

[55fairlane]

Thanks for all the suggestions. Currently enjoying a fresh dose of Covid, but I'm hoping to get back in the shop this coming weekend.

Using my abundance of free time this week to try to wrap my head around FreeCad.

I just got over round 3 of covid.....it sucks...... I had a similar issue with no PM machine several years ago.....I found the voltage coming into the house was varying a few volts.....I think a faulty neutral wire at the pole was the final.....have an electrician do an amp draw on the machine, the panel & house

 

[jfisher34]

Were you able to resolve the issue?

 

[Red96]

@jfisher34 - Recovery hasn't proceeded as quickly as I'd hoped, so I haven't made it back out into the shop quite yet.

 

[Homeshop-26]

Was wondering if any other PM users have/are experiencing this. My lathe spindle speed will drop 100-200 rpm for no apparent reason for a few seconds and then return to the set spindle speed. Bearings are not getting hot, no apparent drag in the geartrain. This started about a month ago - speed dropped while machine was running freely, then returned to normal speed. I noticed it only due to the change in tone, and thought to myself 'That was weird'. Didn't do it again for a few days. Now it is happening more and more frequently, so I'm starting to get a bit concerned.

I've sent an inquiry about the issue to PM, but thought I'd throw it out here, as I said above, just in case somebody else has noticed something similar or it is a known issue. Will follow up on here when I hear back from PM.

Sounds like a potentiometer or loose connection on it. Unless there is some sort of surge on your incoming power feed ( loose plug, surge from the street, someone spiking the power in the house with the dryer, air conditioning, etc.)