Commissioning Brushless Servo Motors


Thread Starter

Rob Hammond

Could anyone suggest the procedure for matching hall sensor signals with their respective phase voltages?
Also, if I were to take guesses on a trial and error basis to find the correct order (of 6) can the motor be damaged?

Rob Hammond

Cameron Anderson

Is this for a sine drive or a trap drive? Taking guesses will(should) not harm the motor. I have done many motor files for someones servo to someone elses servo drive, haven't let the smoke out yet.

The phases should be labeled. If not, contact the mfg and get a pin out or wire diagram. Each mfg is different on their lables, but phases usually match by letter or number.

You might see motor phases 123, UVW, RST and same with hall phases. If motor is UVW, halls are 123, then U-1, V-2, and W-3 are the matches.

You can use a 4-channel O-scope and connect the 3 motor phases and then 1 hall at a time to see the relationship.

Whose motor and whose drive are you using?
Hi Cameron
The drive is sinusoidal. The supplier of drive and motor is HPB based in Taiwan, I believe.

The phases are identified as uvw from the wire colours and I am also able to identify the hall wires u /u v /v w /w.

The problem I have is in entering parameters in the MotionView configuration software...but according to what you say it will probably be listed as "Hall Order 0". It also asks whether or not the Hall signals are inverted - is this often the case???

Many Thanks

Alex Ruderman

Hello Rob,
I've found in my archive a 10 years old hand-written note named "Hall Signals Identification".

This is actually a self-commissioning procedure that enables Hall sensors signals matching for an arbitrary motor phases connection to servo amplifier.

The note contains 9 pages including 3 pages with 8 drawings - too much material to reproduce here. I could send them to you either by regular post or by fax.

[email protected]

PS. Stimulated by this old research I then developed position initialization procedure to eliminate magnetic alignment movement of an AC (sinusoidal) brushless motor with incremental
encoder and without Hall sensors.

In the absence of position Hall sensors, the known technique is to put rotor into predetermined state by feeding two motor phases (180 el.deg. trial movement in worst case).

My technique eliminates long initialization movement for an arbitrary initial rotor position - trial movement is just some encoder counts.
actually I have answer for all your questions,but I have to say it is big amount of information..
first...About damages in the motor I am sure it will be O.K. if control unit or friquency amplifier in same power dimension with motor... PMSM have normal 1,9 overload possibility and amplifier limited usuall up to 100% from nominal..But I have bad expirience damaging control unit,therefor it is necessary to limit output power of amplifier untill 10%, ,or input control reference signal to minimal 10% of nom.revolution - in this case the motor and amp. in safety.

Second... about application and sensor's recognizeing, I know 3 ways:

1) six combinations changing. The best special in fields conditions(not forget about resolution and output power limiting)

2) oscillograph(cope),I've used 2-chbut know better 4ch(not forget about opposit direction of EMF in Generator and Motor's condition, by this way you have to drive the motor as generator and after recognaizing of COMMUTATION SEQUENCE change 1 and 3 Hall sensor), but sometimes Hall-sensors without output resistance show quite funny diagrams - be careful.

3)At Hanover Industrial Exhibition I´ve seen small unit (Hall-sensor-SEQUENCER) you connect 3 phase, 3 Sensors, drive Motor by hand and it's all- you have all number and exact for thus direction or rotation, I suppose it mast be very easy to make it home.
I know some idustrial methods, there are all for laboratory practical asset.

If you´'ll read "":
you can find all what you need-

Installation Notes,
Application Notes,
Be careful it is very important to know in which phase switch setting are the motor's hall sensors - 60 or 120 degree, see "COMMUTATION SEQUENCE TABLE"
third...about Hall sensors. you know the best tipe of H-s is Push&Pull, and now mostly used, but sometimes you can meet a motors with only push or pull tipe in this case you have to invert setting of friquency inverter.
If you need any documantation about PMSM, FPM,or other tipes of Motors or generators send me email to: [email protected]

Could you help me probably to...?
I am intrested in practical,namely,practical calculation of wiring a synchronous generators and motors special (PMSM - oil or liquid cooled), optimisation and anlyse of PMSM related to thermal and electrical unloaded, loaded and overloaded characteristic in generator regime...

Best Regards,

Cameron Anderson

Since the motor and drive are from the same mfg, they should have all the information for you. Does their software allow you to select the motor model number? Is there a setup wizzard? The pin outs of their drive should match their motor.

Davis Gentry

This is commonly done with our controllers for startup of a new machine if the Hall orientation is not known in advance. It can be done by forcing the motor to phase positions and recording the states of the Hall sensors.

Davis Gentry
Delta Tau Data Systems
It is imperative that your drive supplier provides the Hall/BEMF phasing criteria for the drive's commutation requirement. This is what matters for optimal commutation/torque/force generation of any motor. Some drive mfgs
use phase-to-phase and some may use phase-to-neutral. Of course the 3 phase pairs and Hall sequence can vary by mfg. A two chan scope will do.

Just compare signal 1 with 2, then 2 with 3 to get the 123 phase relationship. Pay attention to exact Hall/BEMF offset or error. MAKE SURE

Some "incorrect" commutation results are no brainer, e.g. locked rotor effect, runaway with closed loop control (CAN CAUSE MOTOR/MACHINE DAMAGE IF PROTECTIONS NOT PROPERLY SET).

Some somewhat incorrect commutation conditions e.g. wrong Hall offset (usually associated with digital drives using hybrid Hall/encoder
commutation scheme) can result in "bad" spots every magnet pitch or excessive current draw/heating that may not be noticed until too late because the velocity and position tuning can mask over the inherent roughness of poor commutation. The Hall/BEMF pair phasing should be within 10 degrees of required for minimal affect on performance. Error mostly due to mfg tolerances etc.
Hello Alex,

I saw your answer to Rob through internet search.
I am working on commutating a motor with incremental A-B-Z chanell encoder only. So I am interested in your commutation method without Hall sensor.

Could you give me more info on your method?