Unknown engine help

Hello all,

I found an old engine in the garage and I would appreciate any help on how to make it work. It's from an old dental chair from the UK from what I could figure out. I'm ready to take any measurements or try anything that might help..

Thanks in advance for your help.

How about a motor tag? it would be helpful to know what the motor was designed to operate with.

The chairs that I have worked on that were 120VAC, required a start relay, a current type, or a voltage type, with the addition of a start capacitor. And it looks like you have enough motor leads to require those additions.

SAF Ω

A clue to what might be expected is whether it was running the dental drill, or if it was running something else.

The drill might have a fairly high speed motor, and would likely not be an induction motor, a type that runs at a specific speed, it might be a different type, which in english is called a "universal" motor. That type will run on either AC or DC, and does not have a fixed speed.

Unfortunately, without the label which shows the type and maybe the wiring, it is rather difficult to accurately identify the motor type from just the appearance of the motor itself. If there is no label, then you would need to look inside and see what parts exist.

Do you know what it was intended to do? If it had a purpose which required it to be reversed, such as adjusting the chair, than I have some idea of what it might be. having 5 wires suggests an AC capacitor motor of a type which is reversed by selecting the connection where the capacitor is connected. (In the US that is a "PSC" type)

Photos show right angle gear box and square or Acme screw - seems to suggest non drill application

johnoder said:

Photos show right angle gear box and square or Acme screw - seems to suggest non drill application

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yeah, I mistook that for a flex shaft housing laid out straight.

So likely a chair adjustment, and reversible. Could be a PSC motor with a split capacitor winding to control reversing easily.

Hello!

Thanks a lot for your replies.

It's quite large and was used to control the dental chair (up/down). Unfortunately there is no tag, I looked everywhere (except on the inside...)

Do you have some best guess on how to wire it and try to make it spin or do you suggest I open it and look for more clues?

Thanks again!

First off it is a motor not an engine.
Barer chairs are so valuable now a days that to mess it up would be a shame.
Perhaps best to seek advice from a chair restore source.
Custom Barber Chair Restoration - Farmingdale, New York | Facebook

A motor guy would know where to start and what to do, so not as likely to burn it up guessing what wire is for what and what capacitor to use.
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Motor lift not hydraulic lift so might not be from a most valued chair. motor could be used if not burned up with miss wiring.

use a meter and determinw what wires are connected to other wires.

I suspect that two will be found internally connected, and also 3 will be internally connected

michiganbuck said:

First off it is a motor not an engine.

Click to expand...

Accept it for what it is- this is a failure of interpretation. OP is in France. En Francias, C'est la meme chose... I'l ny'a pas de distinction... the word THEY use for 'motor' literally translates to the word we use as 'engine' because WE actually misuse the framework of the orignal word. It's roots are from the word closest to our "Engineer", where in Romance language family (French, Italian, Spanish) is predominantly a noun- one who uses exercises 'ingenuity' to design or build something.

Smirtix- I see six wires. Je suppose que deux fils vont à l'armature, deux fils vont au champ et deux fils peut-être un frein?
Si c'est le cas, inversez la polarité de l'armature ou du champ pour changer de direction. Le champ et l'armature peuvent être en série ou en parallèle.

The motor appears to be the type suggested by JST.

A Permanent Split Capacitor Motor combined with a gear box.

A PSC motor typically has a low locked rotor torque.
Noting this is a gear box application that is used in an INTERMITTENT application,
there are high-torque PSC motors built for intermittent duty.

I'm guessing at the connection based on the number of accessible (exposed) leads,
and the known purpose of the motor.

The two leads going to the capacitor are likely tied internally to the same leads going
to the reversing switch. The capacitor value is the unknown.
It's not likely higher than 20 MFD. Certainly more than 5 MFD(Could be totally wrong.)

John