[Coolball]

I scored on a deal around Christmas and added a solid old full height drill press to the shop tool collection. Needed a new chuck and the wiring was ... for lack of a better explanation not up to par. It was taped together and fell apart when I barely touched the cord.

So I remade the connections but apparently not correctly as the motor now starts when ever I plug it in with the switch set to off. The motor is a two speed and has 3 wire conductors coming out of it attached to Hi, Low, and Common. The switches (there are two switches, one is for a table light and the second for the motor) are wired partly together as per the attached diagram. It works for me but what I'm stuck on is how to hook up the motor.

Can't have the best of both speeds without changing the switch so I have two questions

-which setting is better for a 12 speed drill press hi or low?
and
-how do i wire the motor accordingly?

[dannronn]

I would use Hi speed. In the switch box connect the white wire from the cord to the common wire on the motor. Connect the black wire in cord to one side of the switch and the Hi speed wire from the motor to the other side of the switch. Make sure you connect the green wire in the cord to the frame of the drill press( lug it under a screw) and make sure green is hooked to the ground prong on the plug.

[Coolball]

Runs perfect, thank you!

[Stale Trooper]

Hey DannRonn,
I have a similar drill press, but I want to put in a rheostat to control the drill speed, and add a light that would come on, and stay at full bright when the motor is turning any speed. Any suggestions?

[Old Fool]

You could add a spdt toggle switch in the black wire that is coming from the on/off switch..then put the hi speed wire on one side of the toggle switch and the low speed wire on the other side of the toggle switch.
Now you can select hi or low at the flip of a switch !

be sure the toggle switch is motor rated for the amps your drill motor is labelled at

[dannronn]

There is no way to vary the speed on a AC single phase motor, if it slows down to 80% of full load speed the start winding kicks in and will burn the motor up. If you had a DC motor there are lots of ways to vary speed but not torque so it would seem to run out of power at lower speeds. Also if you switch between high and low speed as mentioned in the above post I would use a double pole swwitch. On off on, three position or Hi off low. If you use a double pole 3 position switch (toggle) you can jumper the poles together and double the current carring capacity o the switch. Power to the middle 2 terminals Hi to one outer pair of terminal and low to the other pair.

[Stale Trooper]

OK, Thanks. I guess I'll just continue to use the tapered stack pullies that came on it.

[1971BB427]

Originally Posted by dannronn

There is no way to vary the speed on a AC single phase motor, if it slows down to 80% of full load speed the start winding kicks in and will burn the motor up. If you had a DC motor there are lots of ways to vary speed but not torque so it would seem to run out of power at lower speeds. Also if you switch between high and low speed as mentioned in the above post I would use a double pole swwitch. On off on, three position or Hi off low. If you use a double pole 3 position switch (toggle) you can jumper the poles together and double the current carring capacity o the switch. Power to the middle 2 terminals Hi to one outer pair of terminal and low to the other pair.

Totally wrong. There are numerous companies selling variable speed drives for AC motors, and they can allow a AC motor to go down to a creep speed. Old AC drives had issues with surging when the speeds went too low, but newer drives are almost as smooth as a DC drive system.
AC drives for single phase motors vary frequency, not voltage, so they avoid the issues of low voltage that used to burn up motors. By varying frequency rather than voltage the volts stay at 120v., but frequency varies from zero to 60hz.
They're also much cheaper and priced low enough for us hobbyists now.

[dannronn]

A single phase motor has a mechanical switch inside that cuts the start winding and capacitor ( if it is a capacitor start motor) out at approx. 80% of full load speed. If you use a VFD on this type of motor at low speeds the start winding and capacitor will be energized and burn up after time. But you can use a VFD on a permanent split capacitor motor as they are designed so both start and run winding are energized all the time and the capacitor gives enough phase shift to start and run. VFD's were designed to vary the speed on 3 phase motors with frequency modulation and constant voltage therefore giving constant torque. You can also buy a single phase VFD that will give you a 3 phase output which comes in handy if you have a 3 phase motor but only single phase power. DC motors can vary speed by a variable resistance in series with the shunt field (called field weakening) if it is a shunt motor. On the other hand a permanent magnet DC motor can vary speed only by varying the voltage with some kind of SCR drive, or a high wattage variable resistor ( not recommended , lots of heat).

[35terraplane]

I will let the others fight about how to wire it. But you should hook up both speeds if it is a two speed drill press. Running to high of rpm can burn up bigger drills because you are not running the right surface speed for the drill and the material you are drilling. You should get a chart so you know what surface speed you should be running. the bigger the drill the slower the rpm's. they can drop down to as low as 2-300 rpm's for big drills, up to 10-15,000 rpm's for smaller drills. I know your drill press won't turn those kind of rpm's but that is what it takes for small drills, some go up to 30,000 r's.

Then too, you have your feed rate, if you try to push the drill to fast it will burn up. Of course this is all mute if you have a lot of money to buy drill bits.
If you can get good bits from a supply house, if you can find one that sells to the public, or find a buddy that works in a machine shop, they might get them for you.

Bob

[1971BB427]

Originally Posted by dannronn

A single phase motor has a mechanical switch inside that cuts the start winding and capacitor ( if it is a capacitor start motor) out at approx. 80% of full load speed. If you use a VFD on this type of motor at low speeds the start winding and capacitor will be energized and burn up after time. But you can use a VFD on a permanent split capacitor motor as they are designed so both start and run winding are energized all the time and the capacitor gives enough phase shift to start and run. VFD's were designed to vary the speed on 3 phase motors with frequency modulation and constant voltage therefore giving constant torque. You can also buy a single phase VFD that will give you a 3 phase output which comes in handy if you have a 3 phase motor but only single phase power. DC motors can vary speed by a variable resistance in series with the shunt field (called field weakening) if it is a shunt motor. On the other hand a permanent magnet DC motor can vary speed only by varying the voltage with some kind of SCR drive, or a high wattage variable resistor ( not recommended , lots of heat).

I wont disagree about capacitive start motors, but not all single phase motors have capacitor start, which is centrifugal. I've been a licensed electrician for over 35 yrs, and I've installed enough frequency drives on single phase, 3 ph. and DC motors to know what can or can't be done.
AB does make frequency controllers for capacitive start motors also that work, and wont burn up these motors. Not sure how many others also make them. But thesee are not controllers that the average hobbyist would spend the money on, as there are cheaper options, like buying a drill press with pulleys to change speed.
No offense, but I don't need a class on how single ph, 3 ph., and DC motors operate.

[dannronn]

Only 35 yrs?

[Stale Trooper]

Originally Posted by 1971BB427

AB does make frequency controllers for capacitive start motors also that work, and wont burn up these motors. Not sure how many others also make them. But thesee are not controllers that the average hobbyist would spend the money on, as there are cheaper options, like buying a drill press with pulleys to change speed.

Thanks 1971, can you share who or where 'AB' is?
How can I tell if my motor is a capacitor start or not?
I know some variable speed controllers allow the motor to start at full speed, then "dial down" to slower speeds. I would have no problem with that; I'm just looking for an easy way to quickly adjust the drill speed depending on what sort of material I'm drilling, without changing the pulley configuration.
Being retired, and a semi-professional 'tinkerer', and ameteur inventor, I work with wood, plastics, aluminum, steel, & cast iron to name a few. My drill bits range from the smallest numbers (#1) to 1" plus hole saws up to around 4".
Along with that, (being retired), I, naturally, want to keep the cost down (any possible sources for used controllers? IE: what else would use one?).
I hope this explains my needs better.

[dannronn]

AB (Allen Bradly) GE, Westinghouse , Cuttler Hammer, Square D, Siemens, and hundreds of offshore companies all make VFD's ( variable frequency drives) Their products can be found on line or in local electrical wholesale houses. None are inexpensive. The picture is a single phase capacitor start open drip proof motor. The oval thing on top of the motor is the capacitor. Some single phase motors are called split phase motors and don't have a capacitor but do have a start winding that will fail at reduced speed because the centrifical switch inside the motor closes and puts power to the winding which is only susposed to be powered for an instant at a normal start. There are other types of single phase motors such as shaded pole, consequent pole like in a fan motor but they are under powered and will not run a drill press. iF WE REALLY WANT TO GO BACK TO THE OLD DAYS, I have a repulsion start induction run motor on an old machine tool that is older than me but works better than I do at 70 yrs, LOL.

[Old Fool]

Cheap freq drives are around $200 +/-