Now I'm not sure if it is a J2 head. It is a 1 hp , belt pulley type not the
variable.
I have plans on making the rotary converter, but was just wondering what the
big deal and headache was to trying to find a single phase motor instead.
Thanks for the info and I would like to see the "adapter plate" idea that
Russ is talking about also.
"DoN. Nichols" wrote in message
...
In article ,
Ron Coffey wrote:
Is there a replacement from a 3 phase to single phase motor for an older
J2
type bridgeport head? Around a 1 to 1/12 hp.
Those motors are rather special to Bridgeports, and rather
expensive -- especially the pancake-style ones used for the variable
speed heads (and I think that the J2 is a variable-speed, and I *think*
also a 2HP motor, not 1 or 1-1/2 HP. When rebuilding the motor on mine,
I had to spend something like $800.00 just for a new shaft with a rotor
already installed -- with the old one as a "core charge". Consider the
complete motor as being significantly more than that -- and even more
wired for single phase. (I'm not sure whether there is sufficient room
in that housing for a centrifugal switch, which would be needed for the
single-phase version.)
The only time that replacing it might make sense is when the
motor is damaged, and has to be replaced anyway.
Instead -- why not *make* three phase for the Bridgeport?
You have two reasonable choices, starting with a 240V outlet in
your shop.
1) Build a rotary converter out of a larger three-phase motor.
(A 3HP would be plenty. A 2HP would probably do for the 1HP
version.) A google search for "rotary converter" on this
newsgroup will pick up tons of discussions on how best to do
this.
2) Pick up a VFD. This gives you the ability to vary the speed
of the motor as well. Do a search for "VFD" on eBay. Look for
one about 50% higher horsepower than your motor to allow for the
fact that is running from single-phase instead of three-phase.
There are a couple of suppliers often quoted when this comes up.
I remember "Dealer's Electric" as being one of them, but I
forget the other name. Someone else here will almost certainly
post it.
Option (1) would probably be cheaper, unless you are really no
good at scrounging. Option (2) gives you more control of the motor.
And I'll bet that it will be a lot cheaper than finding a single-phase
motor which will fit the Bridgeport. (Especially if the Bridgeport has
a variable-speed head, in that the motor has a *long* keyed shaft about
1" diameter which drives the fixed and sliding halves of the
variable-speed pulley.
Good Luck,
DoN.
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