Motor Identification - Page 1
Forum section: electronics / repair

author: JtroTechAB
author_rank: Contributor
timestamp: May 16, 2019, 05:15:21 am
content: Hello,I have this motor (see attached Image).I think it is Servo motor but I am not sure, kindly clarify.As you can see there are three pins from the windings, how to identify them?

author: JtroTechAB
author_rank: Contributor
timestamp: May 17, 2019, 03:32:36 am
content: Not sure about the type of motor. If anyone can explain.

author: John.S
author_rank: Contributor
timestamp: May 17, 2019, 10:07:38 am
content: Hi,It looks to me like a 3 phase asynchronous motor by the look of the coils and 3 connections coming out.When you have 3 phase supply of the right value, it does not matter how you connect this 3 poles, it will run in a certain direction.To change direction, simply interchange 2 connections.From photo i can not see if the coils are connected Y or D, so you need some motor plate or datasheet to know the voltage needed.greetings John.

author: JtroTechAB
author_rank: Contributor
timestamp: May 17, 2019, 10:49:10 am
content: Quote from: John.S on May 17, 2019, 10:07:38 amWe dont have datasheet of this motor. But it has DC driving circuit.

author: Gyro
author_rank: Super Contributor
timestamp: May 17, 2019, 10:53:31 am
content: We really need to see a picture of the rotor to be sure.

author: JtroTechAB
author_rank: Contributor
timestamp: May 17, 2019, 11:13:00 am
content: Quote from: Gyro on May 17, 2019, 10:53:31 amFind the attached picture of the rotor.

author: amyk
author_rank: Super Contributor
timestamp: May 17, 2019, 11:43:37 am
content: I believe that's a switched reluctance motor.

author: Gyro
author_rank: Super Contributor
timestamp: May 17, 2019, 11:47:00 am
content: ^ Likewise. There are no copper end rings to suggest that it's an induction motor.

author: JtroTechAB
author_rank: Contributor
timestamp: May 18, 2019, 05:07:59 am
content: Is there any way to confirm which type of motor it is ?the only thing I am sure about it is that it works on DC supply.I also implemented the driver ckt (see attached file)with changes in resistor & capacitor value as I wanted 20KHzand as you can see the expected output waveforms in the attached file but in the output I am gettingcontinuous straight line, why is it so?

author: Gyro
author_rank: Super Contributor
timestamp: May 18, 2019, 04:50:04 pm
content: The shape of the pole pieces and the 'lobed' shape of the laminated iron rotor are pretty conclusive, it's a (switched) reluctance motor.Think of it as a stepper motor without any permanent magnets. The lobes get attracted to whichever combination of poles has the strongest magnetic field. By varying the signals on the three inputs, you can control the relative (not absolute) position. I would expect to see the windings driven by three H-Bridge drivers to be able to take combinations of windings high or low (if it's from a DC supply).The circuit you show seems to be for a standard pulse width controlled servo, eg. A radio control model one. That's not what it is (unless there is an additional driver board that you are not showing us).Similar motors are used as 'syncro receivers' (google both these and reluctance motors!) where the 'syncro transmitter' has a winding on the rotor which is driven (normally) at 400Hz AC. These are used for accurately transferring angular motion in an Aircraft. This is not a DC application though, and you seem convinced that it has been run from DC (which would need to be via a power driver as I indicated above).https://en.wikipedia.org/wiki/Reluctance_motorhttps://en.wikipedia.org/wiki/Switched_reluctance_motorhttps://en.wikipedia.org/wiki/Synchro