# Bridgeport spindle motor conversion



## zeusrekning (May 27, 2008)

I just acquired an old Bridgeport mill (series 1 , J-head with step pulley) with a 1hp three phase motor.
With this I got a static phase converter witch will put me at approximately .66hp .
I have not tried it out yet but I am used to running 2-3hp varable speed B-ports and think I will need more power
The options I am looking at are as follows along with cost , advantages in green and disadvantages in red.
1: Rotary phase converter $350-$450 - Get close to full power, able to use with other machinery should I get more. - Stuck with Max of 1hp with current motor.
2: Single phase conversion Similar to http://cgi.ebay.com/SINGLE-PHASE-CO...goryZ632QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
 I would prefer a 2-3hp motor $275-$475 - No phase conversion needed, increase HP, simplisity. - Unaware of any disadvantages other than finding the best motor.
3: A DC motor conversion similar to http://truetex.com/dcdrv.htm $depends on components found - Source power is 120 VAC single-phase house current instead of industrial 3-phase service. 
Infinite variable-speed control of the motor. Full torque at lowest speeds without changing step-pulley belts. DC motor characteristics are better matched to task loads compared to AC motors. 
Main disadvantage is cost of components and putting it all together. This one is more over my head than the other two options. 

The main thing I need the Hp for is tapping holes up to 5/8" dia and maybe an occasional 1"-8. Right now the 1" tap on my 3hp machines at work is ok if using a decent tap.
I like the advantages of option 3 and may look at going this route if what I have will hold me over for a while. 
Are there any options I am missing. What about any advantages or disadvantages I may have overlooked. 
As of right now I'm not planning on acquiring any more machinery. And I am planning (if I have to do this quickly) on buying a face mount 2-3hp 220volt single phase reversible AC motor and making an adapter plate and probably a spindle modification.
I promise to do a thourough write up no mater which way I go. Stay tuned shortly for a post showing my new toy.
Tim


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## Lew Hartswick (May 28, 2008)

If it has a single phase motor what are you talking about the static phase converter and the .66 HP bit????
  ...lew...


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## Cedge (May 28, 2008)

Tim
I didn't pay any attention at all to the machine's specs. I assumed it was already wired for 220 single phase when you were talking to Dan. He'd been running it and all I saw was single phase service in his shop. Is it a 3 phase motor or single phase motor? If it's single phase, it should wire directly into your 220 volt service with no need for a static phase converter or anything else. If it's 3 phase, the converter you have should get you going until you can swing the cost of making the change to something more efficient. 

Give me a call when you have a moment. I'll be over around Pickens in the morning, but you can reach me on my cell phone.

Steve


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## zeusrekning (May 28, 2008)

Sorry guys, it is three phase. Proofreading was never a skill of mind. My eyes follow the words and my head is playing the latest radio tune I heard :-[ . 
So a 1hp 3phase motor using a static phase motor with a 33% loss is .66hp. 
I'm hopeing I can limp along with what I have for a while. I just wanted to see what opinions were floating around the HMEM crew.


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## lathe nut (May 28, 2008)

zeusrekning, I can say that I got the Harbor Freight lahte with the 3 HP 3 phase, got a rotary converter from American Rotary Corp. , works great can do repeat starts with out a problem, Lathe Nut


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## CallMeAL (May 29, 2008)

How about using an inverter?

http://www.leeson.com/products/stock_drives.htm


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## zeusrekning (May 29, 2008)

CallMeAL  said:
			
		

> How about using an inverter?
> 
> http://www.leeson.com/products/stock_drives.htm
> 
> ...


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## zeusrekning (May 29, 2008)

Ok guys I have an update. The static converter sucks @$$. 
 But the good news. I found (laying around in our warehouse) a 10hp rotory phase converter.Brand new. Old but never used!!!
I works great. 
Tim


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