wiring up a 3 phase 2 speed motor

Hello all,

I just acquired a Feeler S600B drill press. It has a 3-phase 2-speed motor. It currently only operates in low speed range. I have opened the panel to discover 3 wires connected to the switch, and 3 wires dangling inside disconnected. Also, I believe the switch at was replaced because it can only operate as on/off. Later I would like to install a switch with lo/off/hi capability.

I have very limited electrical experience, and have learned on Google to check the windings by measuring OHM's across any 2 out of 3 legs in any combination. I measured 5.3 OHM's across the known good set of wires and across the unknown disconnected wires. So I think both windings on the motor are good.

I would like the re-wire the switch to operate the high speed only, but am not sure how to do it. By looking at the motor plate, it looks like I am currently in 8P configuration. If I want to get to the 4p configuration, do I need to disconnect the 3 known good set of wires and connect them to each other, then connect the unknown disconnected wires to the switch?

After I confirm the operation of high speed, what is a switch with lo/off/hi capability called?

Thank you for your input,

-Dave

May be a dahlander motor.? I can't remember what the diagram looked like for mine. Best place I found for switches was here:
https://www.asi-ez.com/member/x1840-Motor-Switches.asp
ASI makes a switch that does all that and reverses too

Modern VFD and electronics have made two-speed motors more or less obsolete. But Hardinge sold lathes and mills with two-speed motors from 1935 until fairly recently. Those Hardinge machines were mostly equipped with Furnas brand drum switches, one for forward-off-reverse and another for low-off-high. I have a Hardinge mill with a single drum switch that does both direction and speed selection, but I have not seen any other example of that type switch. I don't know if those old drum switches are still made. It might be more practical to use a VFD to power the high speed motor windings and select 30 Hz to get the low speed. Of course, the VFD would allow continuous variable speed control.

Here are pictures of 1940's period Hardinge/Furnas drum switches. The machines had a pair of levers that connected to the switch via long rods. The direction switch has three connectors on each side and the speed switch has five.

Larry

That is a Dahlander motor so any high low drum switch must allow for the jumpers when switching to high. If you want high permanently, just jump the U1 V1 W1. Dave

I would suggest you leave it wired as is and add a VFD. Then set the VFD to go up to 120 or more Hz to do the high speed. Install a pot and just use this to change the speeds.

A vfd would be better , wire for high and slow it down with the vfd...Phil

Phil in Montana said:

A vfd would be better , wire for high and slow it down with the vfd...Phil

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You will get twice the torque out of that motor if you wire it for low when using the VFD. I have two speed motors on both my radial arm drill press and vectrax CNC. The VFD upgrade is just tits.

Karl_T said:

You will get twice the torque out of that motor if you wire it for low when using the VFD. ....

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Dahlander motors are constant torque at both speeds.

Suggest the OP move this to the motors and VFD sub-forum.

I would be inclined to just use 3x 3P contactors (ideally an interlocked set for shorting or feeding UVW1 and a separate one for feeding UVW2, to prevent any shoot-through).

If you go the switch route, the likes of K&N (and likely their US counterparts, perhaps including Furnas) will happily build any switch you can draw - their catalogue has essentially worksheets for how to draw which contacts operate in which positions. You can also buy the parts yourself and put it together like lego. I doubt (but might be proven wrong) that there is an off the shelf part number.

But that's going to be pricey and fairly large.

My old Martin shaper used three contactors for the Dahlander motor. Dave

I should say three sets of three pole contactors.

mdr93906 said:

I would like the re-wire the switch to operate the high speed ...

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According to your diagram, you short U1, V1, and W1 together and insulate those connections. Apply power to U2, V2, and W2.

The switch to operate as off/low/high will have five contact sets. Three of those sets will interchange power between the (1) set of wires
and the (2) set of wires. Two sets of those contacts will short the set of (1) wires to each other for high speed operation.

Many users (me included) of these motors set them to the high range and use a variable speed drive to operate the drill via single phase, providing variable speed which is a handy feature for drill presses.

As noted:
Low speed - power is connected to U1 V1 W1 and no connections to U2 V2 W2
High Speed - power is connected to U2 V2 W2 and jumper connections to U1 V1 W1
So switch power the current motor power input connections from U1 V1 W1 to U2 V2 W2 and jumper connections to U1 V1 W1

A VFD, like the Teco L510 is a very simple install if you want to use single phase power, in this configuration you are better off running the motor on the low speed wiring will it will make more torque/Hp, and running it to 120 Hz. Hp will stay constant above the base speed of 60 Hz. This appears to be a 3Hp 2.2kW motor so you would need the Teco-Westinghouse, L510-203-H1, 3 HP, Variable Frequency Drive 230 Volt, 1 Phase Input, IP20, at Dea

mksj said:

A... Hp will stay constant above the base speed of 60 Hz.

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Yes. And the hp rating at the LOW speed will be HALF that of the high speed. This approach forces the
motor to run at reduced hp rating. Often the typical approach is to wire to HIGH speed and the higher
hp setting.

Sensorless vector drives do an excellent job of maintaing torque down to very low speeds.

The motor name plates indicates 9A on 8P, 6A on 4P; This would appear to provide mote Hp on 8P setting if I am reading the name plate correctly. A constant Hp motor would read the same amperage on both pole settings similar to the one below, which I setup to run on the higher pole setting and over speed to 120Hz.

Hey thanks everyone for your replies. I re-wired to run hi speed and confirmed operation. Now I just need to find a switch.