Reversing Shopsmith Motor Query

dyenf · Post by **dyenf** » Mon Jan 14, 2008 7:16 am

Currently I have modified our Shopsmith's to serve as a Generator/Alternator Test Bench as well as a Magneto Test Bench.

Has anyone looked into reversing the motor. Presently, I have just been removing the entire headstock assembly and reversing the unit to drive alternators, generators, and/or magnetos in the opposite direction. It would be much more convienient to just flip a switch.

I have checked with Shopsmith and their response was that will void the warrenty. I'm more concerned with functionality than warrenties.

Thanks for any assistance.

Fred

dusty · Post by **dusty** » Mon Jan 14, 2008 8:40 am

I don't know if a motor needs to especially wound to be reverseable. But the Shopsmith motor is not advertised (spec'd) to be reversible. On the other hand, the motor that is used in the Power Station is.

The size (gauge) of the wires in the run windings and in the start windings is a critical factor in determining reversibility. The run winding is typically a heavier gauge wire than the start winding.

Both of these motors (at least those in my equipment) were manufactured by the same company.

If I was in need of this modification, I'd take my motor to a reputable motor shop and ask the expert. If he says yes - let him go for it.

Questions: Do you take the headstock off and remount it in the opposite position? Have you considered setting up a second rig that services the "reverse" function?

solicitr · Post by **solicitr** » Mon Jan 14, 2008 9:03 am

Why not simply run your alternators, magnetos etc. from the auxiliary shaft, which turns backwards relative to the quill spindle? Any pulley with a 5/8 bore and a set screw will fit it.

Just maundering, but if you happen to have a leftover 500 table and carriage lying around, you could mount them to the left of the headstock, clamp your alternator to the table, and use the elevation rack to make installing and tensioning the belt a snap.

papapenny · Post by **papapenny** » Mon Jan 14, 2008 10:09 am

Hi dyenf

Years ago I needed to reverse a motor on my 10er, because I didn't have a motor that turned in the right direction so I put the fan belt on in a figure 8 and that made the spindal turn in the opposite direction. I used it that way for several years before I was able to get a larger hp and had the choice of which way I wanted it to turn by switching 2 wires around.

papapenny

mtobey · Post by **mtobey** » Mon Jan 14, 2008 1:47 pm

I do the same on my Unimats- it generates a fair amount dust as it(the belt) abrades itself into nothing. It will not even come close to working inside the powerhead but can be done as a temp externally.

dyenf · Post by **dyenf** » Mon Jan 14, 2008 5:44 pm

Thanks for all your replies and suggestions.
1. There is not enough room to mount another table or I'd consider that option. A down side of this is it would require 4 auxiliary tables to hold the units.
2. I can set up another machine, however that ties up two machines, one for clockwise rotating alternators, generators (which are in the minority) and one for counterclockwise rotating units. I'd prefer to have two Shopsmiths that could handle either by flipping a switch.
3. I do plan to remove the motor and take it to an electrical shop, however I was hoping that someone had done this earlier and would let me know if it was feasible or not.

Fred

paulmcohen · Post by **paulmcohen** » Mon Jan 14, 2008 6:27 pm

I found this interesting article on Google that may be of some help

http://www.metalwebnews.com/howto/elec- ... c-mtr.html

They cover what it takes to reverse a motor and other interesting facts. They also have the authors email address so you can contact him directly.

reible · Post by **reible** » Mon Jan 14, 2008 7:28 pm

Hi,

I have seen this issue come up several times and the response has always been that the motor is not one that can be reversed. I also have heard that you can not get the manufactures information as the is a special order item for shopsmith. If when you take it in and find out, and, if they can rewire it could you please have them do an electical drawing of what they did and post it here??

I have no idea of what your set-up looks like but I did a very quick sketch showing a super simple way of having the headstock stay in its normal position, use the main table and an adapter to hold the part to be tested, use the main shaft of the shopsmith with a pulley... remove the saw insert and put the belt through the hole... use the table to adjust the tension on the belt (you might need several belts depending on pulley size) and have an easy way to spin in either position. Given I don't much about what you are doing but this seems like at least a starting place to go from....

Ed

james.miller · Post by **james.miller** » Mon Jan 14, 2008 10:07 pm

I think I remember a post from someone who received a motor that had two internal wires switched and it ran backward until they switched the wires back.

Your local motor re-builder should be able to look at it and tell you if it can be reversed.

When I took my motor in several months ago the guy looked at it and said Shopsmith, either it is that obvious or he really knows motors. I asked about making it into a 2 speed motor and he said it would have to be rewound, I didn't ask him how much it would cost.

dusty · Post by **dusty** » Tue Jan 15, 2008 7:59 am

I believe this is the thread that Jim in Tucson referenced.

This thread seems to indicate that the Shopsmith motor can be made to run in reverse.

http://www.shopsmith.net/forums/showthr ... ight=motor

If you do this and it works for you - PLEASE post the results here. I think many of us are interested.

Shopsmith Forums