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Author Topic: transformer favor  (Read 9815 times)

stevo42

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transformer favor
« on: October 17, 2014, 03:31:12 PM »
Would you mind taking a look at this transformer posting for me. It looks like what I need to run my 1/2 HP, 240V, 6 amp well pump from 120v, but I'm a little hesitate to jump. If the spic plate looks like it would work, I'm going for it.   Thank You,  Steve

http://images.craigslist.org/00S0S_lje37b4yiyi_600x450.jpg

BruceM

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Re: transformer favor
« Reply #1 on: October 17, 2014, 03:46:45 PM »
That will work, a bit of overkill, but if the price is right...
I like Antekinc.com.  Two of the AN-10464 with the secondaries in series would do your job at 2000 watts total, that would be $200 plus shipping. The Antek toroids have oversized wire and can handle a big surge well.  Toroid tansformers are about 10% more efficient than an E-I conventional transformer.




stevo42

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Re: transformer favor
« Reply #2 on: October 17, 2014, 05:10:12 PM »
That will work, a bit of overkill, but if the price is right...
I like Antekinc.com.  Two of the AN-10464 with the secondaries in series would do your job at 2000 watts total, that would be $200 plus shipping. The Antek toroids have oversized wire and can handle a big surge well.  Toroid tansformers are about 10% more efficient than an E-I conventional transformer.

Whats involved in housing those Toriods? I wonder if my electrician friend would be able to help me with this. The Craig,s list one looks more of a "plug and play" , follow the wiring diagram, job.  I really don't want to say anything to the electrician till I have a game plan from input from you folks that, probably have a better handle on these generator systems.  In short, would installing the Toriod be about the same challenge to get up and running?

BruceM

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Re: transformer favor
« Reply #3 on: October 17, 2014, 06:22:18 PM »
There are step up transformers on ebay that are in metal boxes for pretty cheap, also. 

The toroids are bare transformers, no enclosure, but compact compared to the standard EI units.  They are mounted via a bolt through the center. 


buickanddeere

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Re: transformer favor
« Reply #4 on: October 18, 2014, 01:37:53 AM »
 Actually for motor starting it's not overkill. Being a centrifugal pump water and not a reciprocating compressor this tx should do just fine. I would however hang a power factor correction capacitor on the 240V side that carries 1.5 to 2.0amps of leading current.

BruceM

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Re: transformer favor
« Reply #5 on: October 18, 2014, 01:54:36 AM »
Good point, Buick&Deere, for a conventional transformer, 3kw isn't really overboard for starting the 1/2hp submersible pump. 
Adding some capacitance to improve the power factor would help, certainly.

What value motor run capacitor value(s) would you suggest for his 4 wire (separate start winding on time delay relay) 1/2 submersible pump? (I'm assuming he doesn't want to make a project of determining the ideal start/run values by measuring amps and volts with an increasing series of caps in parallel.)






 


mike90045

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Re: transformer favor
« Reply #6 on: October 18, 2014, 05:48:15 AM »
..........What value motor run capacitor value(s) would you suggest for his 4 wire (separate start winding on time delay relay) 1/2 submersible pump? (I'm assuming he doesn't want to make a project of determining the ideal start/run values by measuring amps and volts with an increasing series of caps in parallel.) 

Most of the pump/motor mfgs have a table of acceptable caps.  UNLESS you have a motor protector circuit box in the system.   Those are only designed to work with the raw motor, no extra goodies.  (I know, I'm in that situation, with a protector)


buickanddeere

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Re: transformer favor
« Reply #7 on: October 19, 2014, 11:31:08 PM »
 I was thinking of hanging the cap right on the 240 terminals of the transformer and have it energized 24/7.

BruceM

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Re: transformer favor
« Reply #8 on: October 20, 2014, 12:25:19 AM »
On the Franklin website, I can only find a chart showing a 15 MF additional motor run cap for a 1/2 hp pump for reducing audible noise.  I've never seen a table of suggested values for a submersible pump before, Mike.  Where did you find this?




mike90045

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Re: transformer favor
« Reply #9 on: October 20, 2014, 08:12:04 AM »
On the Franklin website, I can only find a chart showing a 15 MF additional motor run cap for a 1/2 hp pump for reducing audible noise.  I've never seen a table of suggested values for a submersible pump before, Mike.  Where did you find this?

Somewhere on the Franklin site 5 years ago !  Sorry.

This shows "noise"  caps:  (electrical noise I assume, a motor 90' down a well mon't make much audible noise)
http://www.franklin-electric.com/aim-manual/page-15.aspx
   Do not add running capacitors to 1/3 through 1 HP control boxes, which use solid state switches or QD relays. Adding capacitors will cause switch failure. If the control box is converted to use a voltage relay, the specified running capacitance can be added

here's a vendors page for caps, you have to know what motor & control box it goes into.
 http://www.wwpp.co/franklin-electric-products/franklin-control-boxes-and-parts/franklin-control-box-parts/capacitors/

And here's the page of the KVA required for a transformer:
http://www.franklin-electric.com/aim-manual/page-4.aspx   Dang 3 phase stuff !  Single phase not listed.

BruceM

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Re: transformer favor
« Reply #10 on: October 20, 2014, 03:39:59 PM »
The noise caps are for audible noise, vibration or hum of the pipes, not EMI.  There is no EMI noise generation by induction motors, and they are virtually immune to EMI.  The water pipe carries the sound quite nicely when there is a problem.  I've had that experience plenty of times.

Franklin does list transformer sizes for single phase elsewhere, and about 3KW for a conventional transformer is what they recommended for their 1/2 HP pump and motor.

The caps page is for replacement start capacitors, not run.

Adding capacitance on the power BEFORE the time delay start relay in the control box, as buickanddeer suggested, is not going to affect the contacts or make them fail.   Still, with no good personal experience on capacitance values and how much they will improve start surge, I guess Stevo42 should just skip that for now.  If the genny struggles badly to start it, I'd start by adding 15 or 20 mfd of run cap and see if it helps.

   




buickanddeere

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Re: transformer favor
« Reply #11 on: October 20, 2014, 07:05:41 PM »
For a single phase induction motor with no factory PF run caps.  it's safe to go to 1/3 of the motor's FLA for the capacitor's current draw.thus for a 5 amp motor a cap drawing 1-1/2 to 2 amp is fine .

BruceM

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Re: transformer favor
« Reply #12 on: October 20, 2014, 07:32:58 PM »
Motor run capacitors are rated for volts and in microfarads.  Stevo42 can't order a capacitor rated in amps.  How about a suggested value for his 240v value for his 1/2 hp submersible pump with separate start winding that would achieve your suggested 1.5 amps?

Last time I checked on 120v, 1 uf yielded about 50ma, so 240v would be roughly twice that at 0.1 amp, and 15 - 20 microfarads would be about 1.5-2 amps where you suggest, right?


stevo42

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Re: transformer favor
« Reply #13 on: October 21, 2014, 01:58:40 AM »
Thanks for the information. I bought the transformer for $190 including shipping so hopefully it will arrive in a couple days. My electrician friend took a look at the wiring diagram on the Craig's list add and said he'd help me find someone that could handle this sort of thing. Port Townsend has a large marine repair community
and I know lots of folks around there so I'm sure I can find someone.  With the help of you guys I think I have a game plan and if I need one of these capacitors I'll get it. Would this be something the pump installer would know about, He is a friend of mine.  Thanks again.

stevo42

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Re: transformer favor
« Reply #14 on: October 21, 2014, 03:40:33 AM »
Not sure if I mentioned, the pump manufacturer claimed 2.5 KW was need to start it.