The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Temporarily feeding a panel...
by Potseal
Yesterday at 11:05 PM
Locked rotor, no burnout
by jraef
Yesterday at 01:18 PM
Massive power outage South Australia
by Meadow
Yesterday at 06:46 AM
short circuit??
by Meadow
Yesterday at 06:43 AM
Norwegian power?
by Meadow
Yesterday at 06:36 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
HotLine1 14
sparky 10
sparky66wv 8
gfretwell 8
Potseal 7
Who's Online
2 registered (PoLu, eMeasure), 277 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Page 1 of 2 1 2 >
Topic Options
Rate This Topic
#181582 - 10/16/08 06:23 PM Phase converter
Obsaleet Offline
Member

Registered: 04/05/03
Posts: 361
Loc: Pa
Hi Guys, I need some help with calculating size of phase converter, Line, load overcurrent. The Ice cream maker I am working this up for is 208/240v 30a I don't have access to the motor. It would require dismantling the unit. Any help would be apprciated.


Ob(Phil)
_________________________
Choose your customers, don't let them choose you.

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#181591 - 10/17/08 08:52 AM Re: Phase converter [Re: Obsaleet]
JValdes Offline
Member

Registered: 06/03/07
Posts: 308
Loc: South Carolina
Phil,
Are you trying to get 3 phase,or are you trying to change Hz?

Top
#181597 - 10/17/08 07:25 PM Re: Phase converter [Re: JValdes]
Obsaleet Offline
Member

Registered: 04/05/03
Posts: 361
Loc: Pa
Trying to get 3 phase.
_________________________
Choose your customers, don't let them choose you.

Top
#181598 - 10/17/08 07:52 PM Re: Phase converter [Re: Obsaleet]
renosteinke Offline
Cat Servant
Member

Registered: 01/22/05
Posts: 5300
Loc: Blue Collar Country
The easiest, best way is with a decent VFD .... it will convert single phase to true three phase.

Top
#181601 - 10/18/08 08:55 AM Re: Phase converter [Re: renosteinke]
JValdes Offline
Member

Registered: 06/03/07
Posts: 308
Loc: South Carolina
The VFD will work fine on the motor, but the controls could be damaged.
If all you need the 3 phase for is the motor, give me the motor name plate information. Specifically HP, voltage and current. Or you can go to http://www.kbelectronics.com. Here look for the inexpensive chassis type control. The dimensions will be approximately 4"x4"x2" for controls under 5 HP.

Note: The output of a VFD is not a true sign wave. It is a simulated sign wave derived from the DC bus on board the drive. This output is not as clean as a true sign wave like you would see with a transformer output. That is why you must use caution using motors that are not designed to be used on VFD's. Motors that are VFD rated have magnet wire that is rated for over 1500 volts and in some cases special bearings. Do not let this over concern you. It is just a warning of possible motor failure.


Edited by JValdes (10/18/08 09:04 AM)

Top
#181610 - 10/19/08 07:08 PM Re: Phase converter [Re: JValdes]
Obsaleet Offline
Member

Registered: 04/05/03
Posts: 361
Loc: Pa
Unfortunatly, I would have to dismantle the macine to get at the motor so a VFD would be out.
_________________________
Choose your customers, don't let them choose you.

Top
#181618 - 10/20/08 06:08 AM Re: Phase converter [Re: Obsaleet]
ghost307 Offline
Member

Registered: 05/09/05
Posts: 877
Loc: Chicago Illinois USA
It sounds like you'll need a special motor-generator set; sometimes called a 'rotary phase converter'.
It's a motor turning a generator. In your case, it sounds like you would get one that has a single phase motor driving a three phase generator.
_________________________
Ghost307

Top
#181627 - 10/20/08 04:35 PM Re: Phase converter [Re: ghost307]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6786
Loc: Brick, NJ USA
Phil"
Ronkelectrical.com is a mfg of rotary and static phase converters.

Situation may be (is) they require ALL info on your load, so you may have to take it apart. How can you hook it up if you don't have the nameplate info? Voltage, HP, etc.
_________________________
John

Top
#181741 - 10/28/08 03:49 AM Re: Phase converter [Re: HotLine1]
SteveFehr Offline
Member

Registered: 03/19/05
Posts: 1192
Loc: Chesapeake, VA
Look for the THD rating; a solid state phase converter with an output filter will have low THD, and won't be an issue. They make them specifically for this purpose, it's no different than the inverter on a UPS.

A motor generator may be the cheaper solution, or may not be, solid-state is getting pretty cheap anymore.

Top
#181912 - 11/08/08 04:38 AM Re: Phase converter [Re: SteveFehr]
Obsaleet Offline
Member

Registered: 04/05/03
Posts: 361
Loc: Pa
Just an update,
I let this slide as there were at least 4 other contractors looking at it. Interesting to note I was the only one who questioned the service 100a 1Phase residential. along with this 30a unit was: centreal A/C, oven, full size copier, 1 deep freezer(she wanted to ad 7 more), and the 20 space panel was full. Someone has already and completed the job. She told me it onlt took him 1.5 hrs. She also told me she signed a contract to fill a large order based on this machine before it was even wired/installed.

This being said I would like to know more about VF drives being used as phase converter. Does it effect the control? What is a THD rating? Why would you want to ever use a rotarty phase convertor if you coul use a drive?

Ob
_________________________
Choose your customers, don't let them choose you.

Top
Page 1 of 2 1 2 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals