TheBackShed.com

Home	JAQForum Ver 24.01
Log In or Join
Active Topics
Local Time 06:57 16 Jul 2025	Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Electronics : Change motor speed using a VFD

Author

Message

wesley lemarr
Newbie

Joined: 12/01/2014
Location: United States
Posts: 2

Posted: 10:51am 04 Jan 2016

Copy link to clipboard

Print this post

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

Copy link to clipboard

Print this post

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

Copy link to clipboard

Print this post

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...

Print this page

To reply to this topic, you need to log in.