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Forum Index : Electronics : Change motor speed using a VFD

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wesley lemarr
Newbie

Joined: 12/01/2014
Location: United States
Posts: 2
Posted: 10:51am 04 Jan 2016
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I have a 4 pole induction motor with a Synergized Sped of 1,500 rpm @50 Hz, The question is can I use a VFD to lower the 4 pole motor’s speed and reach a synergized Sped of 334 rpm?
 
oztules

Guru

Joined: 26/07/2007
Location: Australia
Posts: 1686
Posted: 09:44pm 04 Jan 2016
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1500 rpm is very unlikely for a 50hz 4 pole motor... more likely 1440 - 1460.
It cannot be synchronous, it must have slip if there is any load at all.

Yes a three phase motor will run at around 11hz, but your power will be compromised, possibly 3x normal running torque, but prone to over heating... ie won't directly replace a gear box where your speed would drop x5,and your torque would increase x5 to maintain roughly the same power.

If you don't need more torque than originally delivered, then it will probably be fine...... but remember your cooling is now defunct too.. ie the fan will be useless for cooling.... may need aux fan.

If single phase, then starting will be problematic, as the centrifugal switch will not function as planned.



............oztulesEdited by oztules 2016-01-06
Village idiot...or... just another hack out of his depth
 
yahoo2

Guru

Joined: 05/04/2011
Location: Australia
Posts: 1166
Posted: 12:51pm 05 Jan 2016
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find 2jeffs1 on youtube and have a look at his video on vfd diy, that's a good starting point, not all vfd units are as good as what he is using at slow speeds, intermittent use and lighter loading is usually OK.
I'm confused, no wait... maybe I'm not...
 
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