Maximal weight of the motor for a bridgeport serie 1 (clone)

[TRC]

I've bought a Bridgeport series 1 clone (the model with the CVT) for my home shop. I have to change my motor, since I do not have an 600V transformer. I have a 5hp (230V) motor, that only need a C face plate and a shaft made and I'll be good to go. However, the 5hp motor is about twice the weight of the original 3hp motor.

Would it be safe to put this motor on the turret of a Bridgeport (considering my mill is similar enough to the real thing)?

Also, I'm not planning to use all of the 5hp, it could damage the machine. I just had a motor lying around. I do not know if I'll use the turret often, so it would be safe to assume that I will use it frequently (I dont have the fancy vices yet).

 

[rons]

2 cents...

I've seen BP's with 1 Hp motors shudder on some cuts. I've heard about this before too. With a 5 Hp? Does it make the shaking go away, or get worse?

 

[TRC]

2 cents...

I've seen BP's with 1 Hp motors shudder on some cuts. I've heard about this before too. With a 5 Hp? Does it make the shaking go away, or get worse?

As mentioned earlier, I won't be using all 5hp. I just have a 5hp motor taking dust, and putting it on the mill is preferable to having it lying on the ground.

Don't worry, I don't want the mill to end up dancing on me.

 

[M.B. Naegle]

I don't think the weight will be an issue when the machine is sitting there or cutting, but it could be a problem when traming the head. I've seen a few machines with striped gears and broken bolts in the knuckle, just from improper use moving a head around with the stock motor on it. Going to a heavier motor, I think you'll want some kind of overhead support or hoist to take up the weight, and it's going to be tricky to fine adjust it.

 

[TRC]

I don't think the weight will be an issue when the machine is sitting there or cutting, but it could be a problem when traming the head. I've seen a few machines with striped gears and broken bolts in the knuckle, just from improper use moving a head around with the stock motor on it. Going to a heavier motor, I think you'll want some kind of overhead support or hoist to take up the weight, and it's going to be tricky to fine adjust it.

I could also make an easy to dismount shaft and motor, which would make life easier while tramming and etc.

 

[M.B. Naegle]

If it was me, I'd sell the motor to someone who could use it's horse power and buy a smaller motor.

I went through a similar case recently trying to find a motor for an old M-head Bridgeport and wasn't able to find a motor so I adapted a single phase C-face motor. In addition to modifying the mounting plate (which was already an old shop-made piece), I had to make a adapter to fit the OEM step pulley to the motor shaft (too short and too small a diameter). It works, but If I had the option I would have bought an original motor.

 

[TRC]

If it was me, I'd sell the motor to someone who could use it's horse power and buy a smaller motor.

I went through a similar case recently trying to find a motor for an old M-head Bridgeport and wasn't able to find a motor so I adapted a single phase C-face motor. In addition to modifying the mounting plate (which was already an old shop-made piece), I had to make a adapter to fit the OEM step pulley to the motor shaft (too short and too small a diameter). It works, but If I had the option I would have bought an original motor.

The main issue here is that these original motor are about 1k$ and more, while any other motor is easily accessible for $500 and below. I still have the original 575V motor, but converting it to 230V is just too expensive, and I'd rather not pay more than I have to.

But you are right, I'm in the process to exchange it. This 5hp motor is 100 lbs, about twice as the original motor.

 

[Nmbmxer]

There are several 3p 575 transformers on ebay in the $200-350 range that you could use to boost 208 or 240v 3p to 575v 3p. Seems easier than changing the motor.

https://www.ebay.com/itm/2908435415...NdATSnC5SfW0EYUV5xxA/EBeo=|tkp:Bk9SR663sfndYA

 

[TRC]

There are several 3p 575 transformers on ebay in the $200-350 range that you could use to boost 208 or 240v 3p to 575v 3p. Seems easier than changing the motor.

https://www.ebay.com/itm/290843541541?hash=item43b7a04025:g:Y-YAAOxyxU1Q8XzO&amdata=enc:AQAHAAAAoG8f09/VThSJ0YA3i/+Hnx2reh1qqD6cudEdGOkYKWTzSL6lBeqPo+ZHqL9j5yf51TPhKjsvSHg95wENlUGtwpRYaNC+giT4kezsyUGaFvhk+TrhxZa8Hq7QFx1GocbBHOKZcFCgaLPrdOvEziW0Fxjy/Da+5UuhixdF7dmWlEISny8nXttsfayJl/JsmqNdATSnC5SfW0EYUV5xxA/EBeo=|tkp:Bk9SR663sfndYA

Not exactly related, but the link you sent me have a $1k shipment rate...

And I did some research... Those are step down transformer. They input 575 and output 230. Reversing them is quite dangerous for the item. Plus the stepup ones are rare

But I just found a 250$ 2hp motor. While I'm here, are these mills even capable of handling up to 3hp cut? This seem excessive, plus it's rare than a tool is gonna need more than 0.5hp... And I've heard stories about bp's rigidity...

 

[Nmbmxer]

It says $113 shipping for me...

Step up or step down, the transformer doesn't know the difference as long as you don't overload the windings. The only notable difference I'm aware of is the location of the taps and can't get a neutral winding when running the transformer backwards.

I can't say I've ever stalled a BP running at design RPM, running it at 10% speed with a VFD -- sure. A 3/4" HHS drill in steel is a ~ 1/2 hp cut, I think a face mill will run out of rigidity before HP.

 

[TRC]

It says $113 shipping for me...

Step up or step down, the transformer doesn't know the difference as long as you don't overload the windings. The only notable difference I'm aware of is the location of the taps and can't get a neutral winding when running the transformer backwards.

I can't say I've ever stalled a BP running at design RPM, running it at 10% speed with a VFD -- sure. A 3/4" HHS drill in steel is a ~ 1/2 hp cut, I think a face mill will run out of rigidity before HP.

2hp it is then. I don't have any experience with transformers and I need this mill running asap. I'll try to put the original motor when I have more free time.