control AC motor speed

[mr_byte31]

Hi All,

I had old washing machine that is not working any more , I took the motor from it , it looks the same as motor in this pics :

I don't have experience in understanding what is written on the motor !

what is 480/15000 RPM ? is it the range ?
where can I find the HP of this motor?
I believe it is universal motor, isn't it ?

 

[chuckey]

You should take the speed control module as well. this module takes the output of the tacho (brown and yellow wires) to stabilise the speed. For the maximum HP (.5?) run the motor at 15k RPM.
Frank

 

[KlausST]

Hi,

this is a washing machine motor. It has two speeds. One for washing, the other for drying.
It usually needs a motor capacitor to run.

klaus

 

[mr_byte31]

the electronic board is big and i dont know the module that is responsible about the speed control , even if i would find it i don't have any idea how to use it after i extract from the board.

so we have two speeds as i understand 480 RPM and 15000 RPM. so i can select each one using special wiring ?
what should be the wiring to connect the capacitor ?

still I don't know what is the HP of this motor !

 

[FvM]

what should be the wiring to connect the capacitor ?

The suggestion is wrong, there's no capacitor involved in brushed DC motor operation.

It's preferably operated with DC voltage for field winding and armature. Armature voltage is controlled by a SCR, or more likely (with newer washing machines) by an IGBT chopper.

Speed control is primarly done by varying the armature voltage in a wide range, for 15k field weakening may be additionally applied.

 

[KlausST]

Hi,

The suggestion is wrong, there's no capacitor involved in brushed DC motor operation.

True, I should have recognized that it is a brushed motor. Sorry.

Klaus

 

[mr_byte31]

DC motor operation ? I think this is AC motor not DC !

 

[FvM]

It's a brushed DC motor. It could be AC supplied if the field and armatuer winding are series connected ("universal motor"), but more likely it has shunt winding configuration and requires DC supply (through rectifier).

 

[mr_byte31]

DC !
I found a sheet that has the motor number
**broken link removed**

it was classified in the document as universal motor.

so what is the best mode to run this motor , DC or AC ?

 

[FvM]

The 50 Hz specification on the type plate as well as the low field winding resistance suggests that the motor is intended for AC operation with series connection of field winding and armature. But stable speed is only possible with tacho feedback in this operation.

 

[mr_byte31]

ok , so i will let it work with AC supply.
the spin motion stated in the document is 1150 , i was thinking it would be 480 or 15000 RPM !
is there any winding to get a specific RPM ?

 

[chuckey]

mr_byte31 have you ever watched a washing machine in action? See post #8. Its a DC motor .
Frank

 

[mr_byte31]

I am really confused now !

 

[FvM]

Both supply variants exist actually. Newer washing machines have DC chopper, or 3-phase motor with VFD inverter.

As you can see above, I was assuming a DC supply of the present motor, but the motor data suggest AC.

DC supply with shunt connected parallel field winding is possible too, but requires an additional low voltage transformer or SMPS for the low resistance winding.

 

[chuckey]

Doing a Google search on :- mca 38/64 148/zn5, gives a service manual for a Whirlpool machine that uses this motor. They reverse the motor by using a relays on the field windings (I am wrong yet again). There is no proper circuit of the controller other then it uses lots of triacs, so the mean AC volts on any winding is unknown.
Frank

 

[mr_byte31]

I started to follow videos on youtube for the wiring but it seems this motor is not that direct
**broken link removed**

what is meant by 1/2 field ?

 

[FvM]

what is meant by 1/2 field ?

Field weakening, allows higher speed with low torque (during spinning).

 

[mr_byte31]

hmm , Ok.

this mean i need to connect :
- point 2 and point 3
- point 5 to the AC terminal
- point 4 to the AC terminal

this would make the motor rotate with high torque , am i correct ?

 

[FvM]

Yes, correct connection.

 

[mr_byte31]

I already made the wiring as indicated in my last post and the motor works well.

on the motor the RPM is stated to be 480/1500 RPM and in the datasheet it is 1150 RPM

which one should be the actual RPM ?