Electric Speed Control

[sluce]

I have an old Mark 5 with the Emerson 1 1/8 hp motor. I have been doing a lot of turning and would really like to have a slower speed than 700 rpm. Shopsmiths speed reducer is way out of my price range. There are some electric speed controllers on Amazon that say they work for motors up to 3 hp and 20 amps. Is there a reason this wouldn't work on the Mark 5? It's affordable but I don't want to damage the motor. Does anyone have any experience with this?

[ryanbp01]

You may wish to check on eBay for one which is used.
BPR

[BuckeyeDennis]

Can you post a link to one of the speed controllers that you’re considering? VFD’s are normally used with 3-phase AC induction motors. Single-phase AC motors, such as the one in your SS headstock, contain starting circuitry that generally must be used very close to the design voltage and frequency. Or you could be looking at a speed controller that’s designed for DC motors, which definitely would not be compatible with your Shopsmith motor.

[sluce]

This is the controller I'm looking at
https://www.amazon.com/MLCS-9410-20-Amp ... rfoiler-20
Even on eBay the SS reducer is over$400

[RonKlein]

Did you read the note in the description? NOTE: Will not work with soft start or variable speed routers. Will not work with "AC capacitor start induction" type motors.

[sluce]

So I guess my question really is - how would I tell that the Emerson is a capacitor start induction motor?

[beeg]

So I guess my question really is - how would I tell that the Emerson is a capacitor start induction motor?

It is.

[jsburger]

So I guess my question really is - how would I tell that the Emerson is a capacitor start induction motor?

As Beeg said "it is" as are all SS motors. There are no electronic speed controls for a capacitor start induction motor (SS motors). If there was we all would probably have one and SS would have incorporated it and not have developed the Power Pro head stock.

[BuckeyeDennis]

So I guess my question really is - how would I tell that the Emerson is a capacitor start induction motor?

In this particular case, you’d probably have to ask, or maybe look up the motor specs somewhere. On a motor that you can easily see, look for a tubular bulge on the outside of the motor — those are a giveaway that there’s a starting capacitor inside the bulge. Another clue is the sound of the motor. An induction motor should run with little more than a hum. A universal motor, which is cheaper alternative that’s used in a lot of low-end woodworking tools, has brushes, and fairly screams when you run it. Routers pretty much all use universal motors, and boy they do scream. That’s the kind of motor that the controller you were looking at is intended for.

[BobCoates1953]

JackShaftDrive.jpg (159.41 KiB) Viewed 2998 times

Not electric but changes speed for lathe work.
The motor three-speed pulley was moved from motor to jack shaft, and
then add 4" split sheaves pulley on the jackshaft and a split sheaves
on the motor. The motor and jackshaft were mounted on ¾" plywood and
hinged at back. A crank of thread rod was put in the front to adjust
the hinged V to get tension on the belt between the split sheaves
pulleys.
If I remember correctly I bought the pulleys at Grainger. Here is
description from the web site.
Motor SHEAVE,VARIABLE PITCH part 3X273
Single Groove Variable Pitch Sheave, OD 3.15 Inches, 3L Belt Pitch
Diameter 1.7-2.5 Inches, 4L or A Belt Pitch Diameter 1.9-2.9 Inches,
5L or B Belt Pitch Diameter 2.4-3.2 Inches, 3/4 Inch Bore Size, Cast Iron

Jackshaft SHEAVE,VARIABLE PITCH part 3X266
Single Groove Variable Pitch Sheave, OD 4.15 Inches, 3L Belt Pitch
Diameter 2.7-3.5 Inches, 4L or A Belt Pitch Diameter 2.8-3.8 Inches,
5L or B Belt Pitch Diameter 3.1-4.1 Inches, 3/4 Inch Bore Size, Cast Iron

Standard ¾" rod, don't know where I got bearings for jackshaft.