Change motor on a Bridgeport machine?

[Sperstad]

Hello

I`ve been planing to buy me a used Bridgeport machine from the states now. But since almost all Bridgeport machine only can handle 60Hz current, and not 50Hz, this may bee a problem. Here in Norway we have 230v and 50Hz.

But I thought that, if I buy a machine from the states then I can change the motor with one that can handel the 230v 50Hz. Are the engines on most Bridgeports very standard physical (outside the housing) if you know what I meen? I was thinking on how easy it is to mount a motor from the aftermarket. The type of Bridgeport machine I`m planning to buy, is one like this:

http://cgi.ebay.com/ws/eBayISAPI.dll...ME:B:WNA:US:12

What do you thing about a motor conversion on a machine like this?

[gridley51]

Why not buy one of www.ebay.co.uk
Correct voltage and a lot cheaper to ship.
Mark.

[Al_The_Man]

Instead of changing the motor, you could fit a VFD (single phase in-3 phase out), you would need a Phase converter anyway, unless you have three phase 220 or 440?
This would give the the base speed and also allow variable speed.
BTW I would look for one with better than the beat-up ways shown on that one.
What will be the freight??
Al.

[Sperstad]

gridley51: Yes, I could find one there. But there are a bigger selection of Bridgeports on ebay.com. And very often, the sellers att ebay.co.uk don`t send to Norway. Most often they just send to UK or it`s just lokaly pickup option.

Al_The_Man: I have 230v 3-phase available in my shop. The problem is the frequens on the machine (60Hz), and the frequens in my shop (50Hz).

The machine was just an exampel. You`re right, it didn`t look so good. The freight from USA to Norway is very cheap. For a package on 1500kg, I pay $500 (shipped with boat, 4 weeks deliveri).

[Al_The_Man]

Originally Posted by Sperstad Al_The_Man: I have 230v 3-phase available in my shop. The problem is the frequens on the machine (60Hz), and the frequens in my shop (50Hz). .

Then in that case, I would go with a VFD, If it is a 4 pole motor, you can run from 0 to 120hz, 2 pole 0 to 60hz, by the time you change out the motor and modify mounting etc, it would probabally be the same cost, VFD's are plentifull on ebay.
Al.

[ivan sandford]

hi if you visit http://www.assettrade.com/en/auctioncalendar.asp (you will need to register ) there is a current auction in the UK that has loads of Bridgeport mills and there is a list of approved transport company's.
as to the 50hrz-50hrz problem as far as i know you should be able to run a 50hrz 3 phase motor on 50hrz with no problem. (I have worked with American touring bands that had 60 hrz rigging motors we ran them on 50 hrz with no problems) good luck!
Ivan.

[riverrat]

Al I could be really wrong on this, tell me if I am please.
if you run a 60 hz. motor on 50 hz. , would'nt it just run a little
slower? isn't the voltage the primary concern?
an ac. motor is just chaseing the wave form, no?

[Al_The_Man]

Originally Posted by riverrat Al I could be really wrong on this, tell me if I am please. if you run a 60 hz. motor on 50 hz. , would'nt it just run a little slower? isn't the voltage the primary concern? an ac. motor is just chaseing the wave form, no?

For best results you should actually reduce the voltage on lower frequency, The same voltage but lower frequency will produce slightly more torque due to increase in current but if loaded continuously without decreasing the voltage, lower Hz can cause overheating and premature failure of the motor.
A motor is an inductive device and is frequency dependant.
Very low power motors like turntables etc, you would only see a difference is speed but very little failure.
Al.

[riverrat]

follow you clearly Al, on a bridgeport mill the guy should be fine.
right?
never seen a knee mill loaded continuously.
btw Al, you are a wealth of knowledge, thank you from everyone.
dino

[D.D.Machine]

I have had two BP mills that are marked on the front for 60 or 50 hZ
there not rare at all. just a little slower on 50 is all.

[AlanD]

3 phase motor speed controller have become VERY affordable and with the correct choice of controller (and BP motor) will probably READILY accomodate the voltage and frequency issues that concern you - AND - give you a wider and more convenient fully adjustable spindle speed in the same small box. Furthermore, you buy a BJ with 3 phase motor (probably at lower cost than 1 phase).

I recommend you discuss the specifics with your local industrial electrician. The 50~60Hz compromise on power will probably be eliminated by the controller. For VERY heavy machining a fan can be added to ventilate/cool the motor.

Alternatively, in the modern world of global transport facilities, just get an freighting AGENT to quote you for arranging the shipping to Norway from UK or Europe (if the vendor is inexperienced or un-willing to help).

ac[QUOTE=Sperstad;240209]Hello

I`ve been planing to buy me a used Bridgeport machine from the states now. But since almost all Bridgeport machine only can handle 60Hz current, and not 50Hz, this may bee a problem. Here in Norway we have 230v and 50Hz.<snip>

[colin1544]

hello there I had this problem in the UK and thought that when it tripped my first VFD controller there was a problem due to the motor being for the US market of 60HZ but if you get a VFD inverter with programmable frequency input setting you can overcome this because running at 50 HZ increases the amperage and with an unloaded spindle it will draw about 6.5 amps and probably trip your inverter after a short time but if you set it up for 60 HZ input it drops it down to about 3.8 Amps and gives plenty of loading for heavier cuts hope this helps Cheers Colin