[Welder2022]

I am trying to diagnose a pesky spindle control problem.

This is a 10 hp spindle DC machine with wye/delta contactors.

The problem is that the spindle will spontaneously reverse of its own accord, instantly. The problem seems to go away as the machine warms up.

The temperature is t-shirt weather here.

It is a rigid tap machine so it's using the K3 & K4 relays on the 1100-2 board energized at the same time and a 0-10 vdc signal at pin 6 going into the spindle inverter.

The strange part is when I check the voltage at pin 6, the spindle will (sometimes) spontaneously reverse as I touch my test lead to it.

I have enclosed a small chart of the measured voltages vs. commanded rpm.



I am trying to work upstream a bit and check the signal coming from the actual spindle card to the 1100-2 board. I am using the schematic provided

on the ITS website "electrical/CE interlocks" I see the K3 & K4 relays but there is also K7 & K9 in series with no reference as to their control inputs.

The local note says "see zone D2". I cannot find this reference.

I thank you for your help.

[rwskinner]

You don't mention which VFD you have.
For example, the Baldor you can put into local mode and test it to eliminate the VFD from the equation. It sounds to me like a bad connection (loose or corrosion) which is common on these older machines.
Your meter causes enough resistance to change the direction signal. This only happens if a pull down or pull up resistor is bad, but more likely a bad connection allowing the meter to over-ride the intended signal.

I am trying to diagnose a pesky spindle control problem.

This is a 10 hp spindle DC machine with wye/delta contactors.

The problem is that the spindle will spontaneously reverse of its own accord, instantly. The problem seems to go away as the machine warms up.

The temperature is t-shirt weather here.

It is a rigid tap machine so it's using the K3 & K4 relays on the 1100-2 board energized at the same time and a 0-10 vdc signal at pin 6 going into the spindle inverter.

The strange part is when I check the voltage at pin 6, the spindle will (sometimes) spontaneously reverse as I touch my test lead to it.

I have enclosed a small chart of the measured voltages vs. commanded rpm.



I am trying to work upstream a bit and check the signal coming from the actual spindle card to the 1100-2 board. I am using the schematic provided

on the ITS website "electrical/CE interlocks" I see the K3 & K4 relays but there is also K7 & K9 in series with no reference as to their control inputs.

The local note says "see zone D2". I cannot find this reference.

I thank you for your help.

[Welder2022]

It's a newer Glentek spindle drive. Been running fine for a few years.

[rwskinner]

EDIT: I looked at the wrong sheet.
The controller sends a signal to K3 and K4 with are the small solid state relays indicated by the S next to them. They have 5vdc on them all the time and the controller sinks to ground to activate them.
They drive K7 and K9 which are the mechanical relays indicated by the coils. These should be 120 vac. I believe they have the schematic wrong because without my glasses, both sides of the coil go to ground instead on + and N like all the other coils.