[pero81]

Hello,
I need to replace encoder on the servo motor. I have contacted original manufacturer but didn't get any answer so I'm turning to you guys for help. I have attached two pictures of the encoder and manual (see page 8). On the servo drive is a label that says ENCODER 2500PPR, and one revolution of the motor I get 10000PPR.
I would be very happy if someone can help me find replacement for original encoder.

Peter

[Al_The_Man]

The fact it is a AC or BLDC motor you will need an encoder with commutation pulses, U,V,W, shown on the encoder connector.
You also need to know how many poles the motor has, I would suspect 8pole, but if you need to confirm it I can tell you how to find out.
Once you have this info together with the shaft dia, you can obtain a replacement from Renco.
Your encoder is 2500p/r the 10,000 pulses is a result of the control using the pulse edges as a x4 multiplier.
You will also need a double beam scope to install the encoder at the right phasing with the stator.
Al.

[pero81]

Thanks for reply. Please let me know how do I look how many poles motor have. Servo shaft dia is 8mm.

Peter

[Al_The_Man]

If the encoder commutation pulses are still working, then you need to apply power to the encoder, probably 5vdc, then using a meter or a scope, detect how many times one of the Com pulses goes high in one revolution of the rotor, if the encoder is shot then then you can use a scope on one of the stator leads and by turning the shaft externally at low rpm, see how many times the sine wave is generated in one revolution, the encoder method is easiest.
4x is 8 pole, 3 times is 6 pole.
Al.

[pero81]

Ok thanks. Will try that and report.

Peter

[pero81]

Ok I tried one of your metod and it worked. I was using a meter with one cable on minus and the other cable of the meter on the U pulse. The voltage went high (5v) 4 times in one motor revolution. This means that motor has 8 poles. Thanks.

Peter

[pero81]

Hello all, I need some help again. At the end I didn't replace the encoder because it works just fine. Now I have some other problem. Now the encoder is not positioned properly because it was took away from the motor. Then I took the motor to the service company.. They have set the encoder but I'm geting very bad resaults. I'm using MACH3 and DSPMC from vital systems. For example when I run program and I hit pause button I hear sizzling noise from the motor, then it shakes very badly and stop. What is causing that? I suspect that they haven't set encoder properly? Can someone please help me with this problem or can someone tell me how to set the encoder. Thanks.

Peter

[Al_The_Man]

I have posted it here a few times but cannot find it so here goes again.
You need a double beam scope or digital storage unit.
Disconnect the three motor leads and attach a ~1k resistor to each lead, connect all three resistor ends together forming a star point.
Apply power to the encoder and place one of the scope leads to the U hall phase and the common lead to encoder common.
Connect the other channel lead to the U phase motor winding and the common to the star point formed by the resistors.
You need to back feed the motor shaft about 100~200 rpm, I use a DC motor and couple the shafts with rubber hose sleeve.
Adjust the encoder by rotating the body and align the square wave U commutation with the U motor phase phase.
See PDF.
The two referred to above are Vab & Hab.
Al.

[pero81]

Thank you very much. Will try that and report. Thanks.

Peter