This article is from the Woodworking FAQ Collection 2, by multiple authors.
From: email@example.com (Jim McKim)
Date: 18 Oct 90 20:53:42 GMT
In article <1990Oct16.firstname.lastname@example.org.Virginia.EDU> email@example.com.Virginia.EDU (Steve Strickland) writes:
>A question (or two) about motors. I've aquired a few extra motors including an
>extra contractors saw motor (3400 RPM, 1.5 HP). First, the motor needs a new
>starting capacitor (the motor got dropped and the old one cracked and is
>leaking electrolyte---though the motor seems to start fine). Where should I
>look for one of these? Delta? Any electrical supply?
Your best bet is a motor repair shop. Check the Yellow Pages under 'Electric
Motors'. Standard type item.
>Second, I've been thinking of putting this motor on my 6" jointer (Delta DJ-15)
>so I can swap the jointer motor onto my bandsaw. Assuming I change pulleys as
>needed to keep the cutter/blade speeds the same, is there any problem with
>this? The existing motors are both 1750 RPM.
>The Delta catalog has a lengthly table showing the motor applications for the
>various motors. Given the speed and HP, are there any important differences
>between these motors? Is being TEFC (totally enclosed, fan cooled) crucial in
>some applications? And assuming you pulley up or down appropriately, is there
>any reason to prefer a 3400 rpm motor to a 1750 rpm motor?
I wouldn't advise replacing a 1750 rpm motor with a 3450 rpm one and changing
the pulleys for the same output speed. The 2:1 change in pulley sizes is
a pretty radical change from a mechanical engineering aspect. You will need
either a lot smaller drive pulley or a much bigger driven pulley or some
equivalent combination in between, which could result in belt slippage
problems. But since you already have the motors, and pulleys don't cost a
heck of a lot, you could go ahead and try it. You would probably want to
work out pulley diameters and a belt length that will give you the same
center to center distance as the old motor. Equations for this are in
mechanical handbooks or design texts.
TEFC motors are needed in dusty environments found on many woodworking
machines. This keeps the windings from getting loaded up with dust and over-
heating and the starting switch inside the motor working OK. Surprisingly,
though, my Sears tablesaw has an open frame motor in the dustiest spot in
the shop and it's still working. I blow it out once in a while, and the
switch didn't make contact once, but it's hanging in there. I figure it is
just a matter of time before I have an excuse to replace it with a 1 1/2 hp
TEFC jobber. Hey!, about that extra motor of yours ...