Author Topic: Nozzle/Head Rotation Motor noisy & therefore struggles to get to required angle  (Read 1269 times)


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I look after 3 x RV4's and 1 x RV1 at my company. I have a fault with one RV4s where the vacuum head rotation motor is very noisy in operation. When off and disengaged from the computer, the rotation wheel can be rotated by finger and can be felt to be nice and smooth. Previously, the motor was graunchy after a Z axis collision, but this was repaired, corrected and the motor was stripped down for a clean and re-assemble, and confirm there was not anything found to be damaged or anything that could impair the motor.
The graunching noise can be heard on arm warm up or when checking tool pick up, it seems to affect the rotation angle as the placed components that are laid are twisted and poorly aligned. Is it time for a replacement motor - if so, anyone got one? Or is it something on the arm control board that ends up with the wrong voltage being supplied to the motor.

Your experience and suggestions would be greatly appreciated.




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If its noisy,
that sounds to me like one of the 5 phases is down.... rather than anything upstream, of the driver module.
once you've heard one, its an unmistakable sound...

it could be a bad connection ( easy enough to check)
a phase gone open circuit in the motor
a driver board.

I would check first by disconnecting the motor connector and checking the resitances of the phases.
I don't know what they should be, but luckily like me you can access a motor that is known to be working to compare meter readings.
If the motor is good,

Obviously check continuity betewen the connector to the motor and the connections in the control box.

then try swapping in a know good driver board

Others might know better ways to check...



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Definitely sounds like a motor phase out. Check wiring at the drive end - with power off, unplug the motor connector from the driver board  - you should measure the same resistance, a few ohms,  between adjacent pins and the outermost pins of the connector. I've had a pin go bad on the big D connector on the bottom of the base unit.

You should be able to check for a bad driver using a DMM diode test range - unplug all connectors from the board, check for a single diode drop from 0v to each pin (dmm + to 0V) and +V to each pin ( Dmm - to +ve supply).
I have some spare hybrids if you need one, but check wiring as a short is a likely cause of a blown output.



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Although it's tempting to check for driver boards by swapping (note some boards have different switch settings), this risks blowing a second board if it's a wiring fault. Guess how I found that out...