Author Topic: 230v dc motor  (Read 5450 times)

Offline shipto

  • Hero Member
  • *****
  • Posts: 803
  • Country: gb
  • Redditch, UK
230v dc motor
« on: June 13, 2013, 04:58:28 PM »
I have a 230v dc motor from a clarke mini lathe. I assume I can run it from the mains with a diode or rectifier in place (please correct me if I am wrong).
Again assuming I can, is there a formula for working out what kind of speed I can expect. The motor is supposed to be capable of 4000rpm which I guess would be a constant smooth supply so a full rectifier will? give me about this maybe more as the voltage will be 240 but a diode would give me 50 hertz at 240 volts and this is the speed I would like to know.
I appreciate any input.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: 230v dc motor
« Reply #1 on: June 13, 2013, 05:15:40 PM »
240 volt mains rectified with a full wave bridge (4 diodes) with a reservoir capacitor should realise circa 380v dc.....

(240 * 1.414.....)

The voltage at this level is too high for the motor which is why it is fed with a modified supply from a speed controller....

The voltage rating of these motors is generally around 180 v dc, this is obtained from the speedo which is either mosfet based or thyristor (scr ) based....

If you want to run the motor from the mains I suggest you use a variac and limit the voltage goign to the bridge rectifier ( suitably rated voltage and current wise......)
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline shipto

  • Hero Member
  • *****
  • Posts: 803
  • Country: gb
  • Redditch, UK
Re: 230v dc motor
« Reply #2 on: June 13, 2013, 05:35:40 PM »
Thanks John I guess i will leave it then as I only want it for a single job I wont bother with this motor and save it for a project where it will be worth buying the proper controller. Was a nice thought while it lasted though.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/

Offline Auskart

  • Jr. Member
  • **
  • Posts: 20
  • Country: au
Re: 230v dc motor
« Reply #3 on: June 13, 2013, 10:38:35 PM »
If you know what you are doing, you can use the speed controller from an old Treadmill.

Offline Pete.

  • Hero Member
  • *****
  • Posts: 1075
  • Country: gb
Re: 230v dc motor
« Reply #4 on: June 14, 2013, 12:06:23 AM »
You want THIS, or something like it. This one is only good for about 1hp:

http://www.ebay.com/itm/221221730576?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

Offline John Hill

  • The Artful Bodger
  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2016
  • Country: nz
Re: 230v dc motor
« Reply #5 on: June 14, 2013, 12:14:53 AM »
If it is just a single job and you don't care too much about anything a half wave rectifier (i.e. just one diode) might do the trick.
From the den of The Artful Bodger

Offline John Hill

  • The Artful Bodger
  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2016
  • Country: nz
Re: 230v dc motor
« Reply #6 on: June 20, 2013, 06:42:06 PM »
Doh! I forget to mention that using half wave rectification would give an effective DC voltage of something less than 230V, depending upon load and capacitance in the circuit etc.
From the den of The Artful Bodger

Offline shipto

  • Hero Member
  • *****
  • Posts: 803
  • Country: gb
  • Redditch, UK
Re: 230v dc motor
« Reply #7 on: June 21, 2013, 06:03:10 PM »
thanks John but I sorted it with a standard induction motor in the end, just needed to power up lathe to do a bit for the lathe drive belts. working on a new stand for it now.
Turns out this life c**p is just one big distraction from death but a good one. For the love of god dont give yourself time to think.
https://myshedblog.wordpress.com/