I have an AEI 240V single phase motor, 1425RPM, and wish to reverse the spindle direction. It's an old motor and possibly a universal brush motor. I cannot see any capacitor, so if it does have one, it's right inside where you can't see it! I shall try to attach a photo of the power connections. There are 2 main terminals with hex nuts securing the wires in place. On the left, the mains power input (Brown wire) is connected to the motor wire (Red). The Blue mains input (Neutral wire) is connected to black motor wire. Is it as simple as swapping over both sets of wires to occupy the other terminal?There is a yellow/green earth wire connected to the motor body/chassis.

 

First question: does the motor run now, when powered with it's rated power??

It is not quite that simple as swapping both sets of wires. BUT, FIRST, do you mean to say that you are unable to see if it is a brush type (universal) motor??
Does the motor have a label that tells the RPM and required voltage
I have a GUESS as to how to reverse it, BUT you must make a resistance measurement to verify if my guess is correct. I am guessing that it is an induction motor, the simple resistance check can verify that.

 

Thank you for your reply. Yes, it runs with power on! I will attach a photo of the label here. Yes, I am a dork for this, sorry, so cannot tell if it is a brush type motor. I don't know how to make a resistance measurement, but I do have an AVO meter.

 

Since it is rated for 1425RPM it is likely a 4-pole induction motor, since that is a typical speed for such a 50Hz motor under load and it will only increase slightly with no load..
Universal motors generally run at a much higher speed, which is highly load dependent.

 

First, make a sketch of the existing wiring connections as is working and an arrow noting the running direction. Appears like brown to red and blue to black.
Check if the underside of the cover has wiring instructions. Or mentions the blue and the yellow.

I would insert a 100W incandescent light bulb in series to a cable that feeds only 120VAC (if you have it) at a bunch of combinations of the internal windings; plug into the wall and check run/rotation. The worst short circuit or error will only turn on the bulb brighter with no harm to anything.
Or, with all nodes disconnected and noted on paper, identify windings continuity.
Try searching the "type" figures on the plate. Is there a capacitor or starting switch in it ?

----> https://search.brave.com/images?q=4...ing+colors+uk+single+phase+230v&source=images

There is also this ----> https://www.model-engineer.co.uk/forums/topic/aei-motor-wiring-for-rescued-lathe/

 

OK, I saw the tag and it is indeed a fout pole induction motor. In post #1 I see the photo of the junction box with the two studs with the brass nuts. Two wires on each stud, and not one bit of the markings legible.
On the upper stud are the blue mains wire and a black wire from inside the motor. On the lower stud are the brown mains wire and a RED wire from inside the motor.
To reverse tghe rotation you need to exchange the positions of the red and black wires, so that the red wire iis on the stud that presently has the black wire. Then, also, the black wire will move to the lower stud that presently has the red wire. Then connect the blue wire to the upper stud the same as it is now, and connect the brown wire to the lower stud, the same as it is now. THAT should reverse the motor rotation.Do not change anything else, only exchange which studs the black and red wires are connected to.

THAT is the common way of changing the direction that a four pole motoe turns.
What you do not see is the other wires also connected to those studs.

What the change I described did was reverse the phase relation between the start and the run windings. At least that is the intent, based on many other similar motors.

 

Dear MrBill2, Thank you very much for your understanding and clear instructions. It WORKED! I now have a bench mountable drill...............which was the desired outcome! Very happy with this supportive community. Thank you once again from a dork in Salisbury UK !!

 

All it takes is " a few years" of experience with 4-pole induction motors, to recognize what you had. I am not at all sure about the other terminal posts and what they would be involved with, though. So leaving them alone is the best choice.
Some motors in wash machine applications do have an extra switch that closes when the motor reaches close to full speed. and a very few have separate connections for an over-temperature cutoff switch. Leave them alone since they are not needed for your application.

 

Actually if refering to the internal centrifugal switch, it opens rather than closes when almost up to speed in order to disconnect the start cap & winding.
BTW, it appears it might be the type of split-phase motors that uses sufficient phase shift for self-starting in the start winding to allow the abscence of any start cap,
Usually seen in 1/2hp and below.

,

 

Clothes dryers especially have a second switching function to assure that the blower is running before the heating is enabled. Mostly gas dryers is where I have seen that second switch.
CERTAINLY the starter switch will open as the motor reaches full speed. Two entirely different things.