Thread: Drill press rewiring: electrical connections with questions

This is a strictly electrical question with regard to rewiring a drill press. It is specifically an Aciera 10T model with tapping attachment and auxiliary light built in. First, the image links:

Drill Press Rewire pictures

I didn't import them because I left them larger in size. The link above is to photobucket where you can see what I have and a wiring diagram. There is one mystery box with a big question mark drawn next to it. My suspicion is that it may be a reversing switch remotely activated by the momentary switch---which in turn is controlled by an on/off switch for the tapping function on the front cover of the press.

The front cover of the press has two on/off switches. One controls a built-in work light. The other activates the tapping function. The tapping function as I understand it works like this: you turn the switch to "tap", set the depth gauge which... at the end of the travel contacts a rod activating the momentary switch. The motor reverses direction when the momentary switch is activated so your tap reverses itself out of the hole.

The other questionable aspect in this schematic is getting single phase 120V power for the light socket from the incoming 220V, 3~ power. I have tried reading up on the "2 legs between ground" approach. I have a multimeter and utilizing two legs of my 220V, 3~ power source with a ground connected as a third line on my multimeter renders a reading of 130V. How to enact this in an actual line wiring application such as this drill press is a little enigmatic to me still, though.

I must admit that laying the actual components out and looking at them in logical fashion makes more sense to me than the manual's wiring schematic. I should also note that the manual is from a 6T model while I have a 10T model. In all practical respects, the two are the same construction but physical size, so the diagram should be correct, but I cannot guarantee it.

Lastly, it should be pointed out that the motor on this machine is a 2-speed, 220V, 3~, 60Hz. spec.

Any thoughts on the labelled picture of the actual components would be greatly appreciated. Thank you all for reading and your suggestions on the correct configuration.

Okay. So I've identified the mystery box as a "Brown Boveri reversal switch". It reverses motor rotation, and is labelled:

Brown Boveri
Typ P 8arf
110V *
60Hz.*
B 501892
*The Volt and Hz designation has a sticker labelling it as such over whatever it was originally.

No replies, huh? Here's my latest attempt at reconstruction:

*One practical question remains: where does a "Neutral"---as opposed to a Ground---originate?
*Incoming power to machine is by way of a 220V, 20A, Twist-Loc 4-prong plug connected via a dedicated wall outlet.
*Wall outlet power is 220V, 3~, 60Hz. generated by a Rotary Phase Converter from residential 220V, single phase power.

I'm certainly no electrical expert, know just enough to be dangerous, but I'm pretty sure you need a small 220-110 volt transformer to generate a neutral for the light and the coil on the reversing switch and possibly even a coil in the main disconnect. Hope this helps, Jim.

Originally Posted by JBishop

I'm certainly no electrical expert, know just enough to be dangerous, but I'm pretty sure you need a small 220-110 volt transformer to generate a neutral for the light and the coil on the reversing switch and possibly even a coil in the main disconnect. Hope this helps, Jim.

I am certainly not an expert at electrical either. I do however run many RPCs

You will either need a 220-110V transformer as Jim describes or pull a neutral from your single phase breaker panel. The latter is most usually what I do while I am wiring the RPC. Then bring the neutral to each location I need it.

Sometimes machine tools have a transformer on board for a work light & the contactor coil if it's 110V

I can follow you with the small 220-110V transformer, but I am unsure where that would enter into the wiring diagram. i.e. 220/110V transformer example

Otherwise, wouldn't running a Neutral line to the machine create a 5th wire to connect---thus negating the option of using a plug/outlet? For example, T1/T2/T3/Ground/Neutral. I looked at my panel and the Neutral is clearly marked.

See if the modified drawing posted below makes sense to you.

If I understand what you are wanting. What I have drawn in should do the trick as long as the transformer is the correct size to power your light.

The transformer creates it's own neutral

Originally Posted by millman52

See if the modified drawing posted below makes sense to you.

If I understand what you are wanting. What I have drawn in should do the trick as long as the transformer is the correct size to power your light.

The transformer creates it's own neutral

I've done what millman proposes. I even did it to an Aciera machine (F4). I would only add that you should ground the locally-derived neutral to the machine's ground which (hopefully) you've already tied to your house ground, and make sure the lamp's threaded shell is connected to the neutral side, not the switched hot side coming from the transformer.

What about using a 220volts light and connect it to T1 and T2 instead of T1 and neutral

Peter from Holland

What about using a 220volts light and connect it to T1 and T2 instead of T1 and neutral

Peter from Holland[/QUOTE]

Good idea, or how about using two 120 volt bulbs in series. I also think you might make a LED ring light and adjust the resistor size so it works on the voltage you have.
Bill D.
Modesto, CA

+1 on 220v bulb. That is the simplest. Google "220 volt bulb" and you will find there's lots available.

No opposition to a 220V bulb, but it does not change the fact that the reversing switch needs a 110V control line to actuate the reversal (the switch is so labelled). Since a 110V must be generated for this, I expect to use it for the lamp as well.

Originally Posted by Arthur.Marks

No opposition to a 220V bulb, but it does not change the fact that the reversing switch needs a 110V control line to actuate the reversal (the switch is so labelled). Since a 110V must be generated for this, I expect to use it for the lamp as well.

That does not show in the drawing ?????
You could also replace that switch with one with a 220volt coil then


Peter from Holland

Hi Peter,
Well, yesterday I decided to wire everything up outside of the drill press enclosure (it is currently disassembled). I didn't want to go through the trouble of fighting tight access and inconvenient wiring only to find out I didn't have it correct. I also would like to point out that the "manual" wiring diagram I linked to is not for an exported, inch spec machine. It is in fact for a totally different wiring voltage altogether (415V/220V control).

In any case, I bought the 240/120V transformer I linked to earlier. To my utter amazement, it all works! The light switches; the tap function activates the reverse switch; the motor reverses almost instantaneously. Frankly, I am impressed with myself. I have always considered myself utterly, electrically challenged.

Originally Posted by Arthur.Marks

In any case, I bought the 240/120V transformer I linked to earlier. To my utter amazement, it all works! The light switches; the tap function activates the reverse switch; the motor reverses almost instantaneously. Frankly, I am impressed with myself. I have always considered myself utterly, electrically challenged.

I am no electrical whiz either. What I know I have had to learn from situations just like you are now in. & asking for help.

When it moves much beyond being able to look at it kind of like water piping, it's pretty easy for me to get lost too.


Glad you have it working. It's perfectly ok to give yourself a pat on the back & a couple attaboys.

Neil