thekman
Electrical
- Sep 3, 2009
- 90
Can you guys help me be sure I'm thinking this through correctly?
I have a 208-230v singlephase 60Hz motor running on a 240v 50Hz supply, and want to get it down to 190v. I am not able to touch the motor, add a VFD, or get different power. I may however, be able to add a transformer near the source.
I was thinking of wiring a 750VA (240/480P 24/48S) (acme T181066)autotransformer in to get 192v, 2995VA, 15.6a.
Using the formula
TOTAL OUTPUT VOLTS X SECONDARY CURRENT (RATING)= VA (192v X 15.6a = 2995VA)
This would be the total available power to my load as I understand it.
The 2HP motor FLA @ 208-230v 60Hz is 11A (only one # for both V on data sheet). I was at the site last week and found it pulling 12a at 240v, peaking around 20a when starting. If I reduce the voltage 20% to meet the V/Hz ratio, I assume the current would rise 20%, which would mean it will go from 12a to 14.4a.
If this is ok, the only hiccup I've got is that the ACME transformer is not CE marked. If you could recommend a European transformer company (as opposed to a random google search)that might have a similar model, it would help.
On another subject, I found the starting cap on the motor was rated 125v. (which blew and was successfully replaced with a 300v cap) This motor is a dual winding 115/230v and I thought the cap should be rated at least 250v if not higher, and asked the motor manufacturer and he said that 125v was correct for that motor, and that only when using a VFD would the cap v rating be 2x or so.
Your input is invaluable. Thanks in advance.
I have a 208-230v singlephase 60Hz motor running on a 240v 50Hz supply, and want to get it down to 190v. I am not able to touch the motor, add a VFD, or get different power. I may however, be able to add a transformer near the source.
I was thinking of wiring a 750VA (240/480P 24/48S) (acme T181066)autotransformer in to get 192v, 2995VA, 15.6a.
Using the formula
TOTAL OUTPUT VOLTS X SECONDARY CURRENT (RATING)= VA (192v X 15.6a = 2995VA)
This would be the total available power to my load as I understand it.
The 2HP motor FLA @ 208-230v 60Hz is 11A (only one # for both V on data sheet). I was at the site last week and found it pulling 12a at 240v, peaking around 20a when starting. If I reduce the voltage 20% to meet the V/Hz ratio, I assume the current would rise 20%, which would mean it will go from 12a to 14.4a.
If this is ok, the only hiccup I've got is that the ACME transformer is not CE marked. If you could recommend a European transformer company (as opposed to a random google search)that might have a similar model, it would help.
On another subject, I found the starting cap on the motor was rated 125v. (which blew and was successfully replaced with a 300v cap) This motor is a dual winding 115/230v and I thought the cap should be rated at least 250v if not higher, and asked the motor manufacturer and he said that 125v was correct for that motor, and that only when using a VFD would the cap v rating be 2x or so.
Your input is invaluable. Thanks in advance.