Thread: transformers

Hello all
Another newbie here. I am not an electrician and not a machinist, but I just bought a new/old toy. It's a Bridgeport series 1, J-head.Right from the start I was figuring on a RPC. After getting this unit home I discovered that the spindle motor tag reads 220/440 (I have not verified this), but the power feed motor tag only reads 440. I have not checked the tag on the pump yet.
So my next plan was to get a 220 primary to 440 secondary transformer. I have had no luck in my online searchs for one of these. Can someone here direct me to a source or is there something else that I should do?
The spindle motor is 1hp,the feed is 1/8hp, and the pump tag is not in a position that I can see but will guess 1/4hp? So i'm thinkin that I will need enough juice to run 2hp.
I am open to other ideas as well (VFD) Any and all help would be greatly appreciated. Rod

Starting with the last, a VFD is usually not a good soultion for a multi motor problem. The VFD has some very nice variable speed capabilities that are difficult to utilize unless you want all motors changeing speed together. Also even a VFD would need a transformer (on the input) if you actually need 440 V.

Transformers are readily available even on Ebay. However, before I went shopping, I would open up the junction box on all the motors and see how many leads are in there. If you find 9 wires, you will not be needing that transformer. Also look at that pump. It could be single phase. Same could be true for the power feed.

Let us know what you find after a full inspections and the responses you get will be a whole lot more applicable to your needs.

And congratulations on the new toy. I assume by your username that your a wood worker. I find the contrast between working with wood and metal to be a little frustrating sometimes. One can make miles of cuts in wood in the time one is setting up for a cut in metal.

Q-swan: I been in your shoes. Bill is right, get all data on motors. I've called tech support at a variety of places(Grainger, MSC, McMaster...) and invariably if those guys couldn't answer my questions, they had the decency to hook me up with a mfr rep. Most of these guys can make sense. If you want to go the transformer route, you could try Chris at solahevyduty.com. They make a lot of the transformers that MSC sells. There should be a ph. # on the site. The 220/440 transformer is a very common item

As to the differences in HP in the three motors, it is a bit of a snag as the transformers are sized to the va number. Post back and let us know how you are doing. There are several much more knowlegeable individuals than me lurking here.

Q'Sawn,

I think I answered your postings on another site but here is another idea. The power feed motor is real small and is not expensive to rewind. Just have it rewound to 230 volts and connect the other two motors for 230 volts and you will have the entire mill operating at 230 volts. This makes it easy to use a RPC to run all three and you need no transformers.
You might even post in the For Sale / Wanted forum here and ask for a 230 volt power feed motor of the same description as you need. You may have one offered at a reasonable price.

The transformers can be a pain and you may have more invested than it will cost to rewind the motor. Do the economics first.

Bruce Norton
Kingsport, Tn

Also, there won't be any transformers with "220 primary". You just hook them up backwards for step up service.

John