Help needed with lathe electrical’s!!

[farmer_joe]

Doing a wiring diagram is beyond me I think.

I have a feeling I’m going to have to try and find someone to look at it as it’s getting more and more over my head.

 

[carbon]

Use a multi meter in continuity or resistance range and with the power disconnected manually activate the contactors and measure from incoming connection to motor output for each phase

 

[farmer_joe]

So,

using the continuity setting on my multi meter also shows ohms.
There is continuity across all 3 phases from the contactor to motor.
Checking all of them shows 6.9 to 7 ohms across 2 and .2 to .3ohms on the third.

does that make sense? If so what is it telling me?

the readings are the same with the contactor in or out.

 

[Memmeddu]

Bypass everything via connecting directly the motor and see what happens .
I'm not entirely but they could have swapped the motor prior selling it to you .
It might be a Delta start star run or vice versa motor .

I can draw a wiring diagram that should work but I need time I will probably upload it after midnight

 

[Memmeddu]

How do I check whether the phases are getting to the motor?

move dragged the lathe out and have accessed the motor, I have the cover off the electrical box there.

While you're there make a photo to the motor data plate and to the connections

 

[farmer_joe]

Got a picture of the motor terminals.

There are a second set of wires going to the terminals, these go to what I’m assuming(maybe incorrectly) is a brake on the end of the motor.

thank you all so for for your help. I’m beat as up early for work this morning so am going to pack it in for the night now.

 

[farmer_joe]

I would appreciate that memmeddu.

I had a look and it looks like the name plate is either gone or on the far side of the motor where it can’t be seen.

currently I feel I’m no further along than I was at the start of the day.

If I get time tomorrow I’ll take a video of trying to fire up the lathe. never know, someone might have an epiphany!!

 

[Memmeddu]

Ok I've studied the wiring diagram and there's nothing to simplify it unfortunately
But I can make a drawing to the things easier anyway
Here is explained what you see in the diagrams and what you see in the cabinet
I've used the same colours
Skipped the overload protections (green) on the wiring diagram but included in your picture

Yellow is the main power contactor

Red is your fuse box , I've discovered that two of them are missing , replace the two missing ones , they should not be necessary because the overload protection modules in green , but in name of safety replace them .

Green as said up above are the overload protections , those or at least every single one I've encountered in my life are not autoreset , you have to push the red bottom to reset them (reason why you should always have access to the panel)

Orange is your main motor power contactors
One is forward the other reverse
Those contactors have 4 normally open contacts
3 of them are the phases and one
is for coil exciting signal (it close a circuit to keep the switch closed without keep your fingers pushed on the reverse or forward push bottoms )
The stop switch will cut the current to the coil on those two contactors

Blue are the change speed motor contactors.
Your lathe has a continuously variable transmission but despite what I was thinking prior having a look to the lathe manual ,the speed selection isn't manually regulated .
But there is a motor which shrinks or spread open the pulleys of your CVT

All your controls have to be live at 110V since your contactors have 110V coils

I'd suggest to firstly see if the motor runs ,so connect it directly to 415V
It has a built in brake ,if it doesn't spins the problem is in the motor itself
So take it a part and check for loose connections

I'd suggest Also to replace all the contactors and lights with some that can be operated using 24V
Fit a auxiliary power transformer in the cabinet

Your motor is just a single speed motor

Hope to have helped little bit .

Try to see if what I've thought is actually the truth

 

[Memmeddu]

Any news

 

[hermetic]

Farmer joe, if those resistance reading are the coils in the motor it looks like one of the coils on the motor is faulty , or your reading is including the brake circuit. If not you could be trying to start the lathe with the brake on it may be stuck with standing unused, but I know nothing of Harrison Lathes, any Harrison men out there know if there is a way of mechanically holding the brake off?

 

[Pete.]

From the info given I would suspect a fault in the motor brake. Does the motor pull round on the belts freely when it's not powered up?

 

[farmer_joe]

No progress as yet guys, been at work all day. Only just finished and I don’t have it In me to go poking around in it tonight.

Funny the brake should come up.
Thinking about it last night and today I think it must be the cause of the problem. Why else would the spindle be trying to turn but not spinning up freely? My wife says it made the lights in the house flicker so it must be trying hard and drawing an awful lot. The 5hp mill with an 8 inch face mill doesn’t cause the lights in the house to flicker.

The brake wires are connected to the motor terminals, so I’m guessing the brake is disengaged by the power to the terminals. And when the power is cut it reengages.

How do I test it though?

 

[farmer_joe]

Pete,

it’s pretty much impossible to rotate the motor pulley by hand.

 

[Pete.]

Ok, so disconnect the motor leads from the terminal box but leave the brake power wires connected. Hit the start button and pull on the belts. If the brake is servicable the motor should turn freely. If there's a fault the brake won't come off and the motor will still be tight.

There may even be a way to release the brake manually via the adjuster. If the lathe has been stood up for a long time it might just be that the brake has rusted together.

 

[brightspark]

try and see if u can release the brake manualy and hold it off . if not take the leads feeding it of the motor and connect them to your converter and power it up only. the motor should spin freely by hand if its working its only an elecro magnet running of 2 of the phases

 

[farmer_joe]

Thanks Pete, I’ll have a look when I get a chance got a busy week ahead.

it sat for 3-4 weeks before reaching me but in that time it was covered up outside waiting to be collected to quite possible the brake has got stuck on.

 

[Pete.]

I doubt it would seize in that short time. Perhaps the power lead to the brake is broken, it doesn't look like what you'd exect for original. Looks like domestic flex.

 

[Memmeddu]

The brake should be nothing more than an internal switch in the motor which shorts out the windings (it will transform the inertial energy in electric as a generator but being in dead short it would force it to stop )
Manual says that the motor features a built in brake , terminal box on it shows only 3 wires so it is inside it

How to see if spins give current directly to the motor

 

[Pete.]

The brake should be nothing more than an internal switch in the motor which shorts out the windings (it will transform the inertial energy in electric as a generator but being in dead short it would force it to stop )
Manual says that the motor features a built in brake , terminal box on it shows only 3 wires so it is inside it

How to see if spins give current directly to the motor

You wouldn't need extra wires for a winding short, it must be electro-mechanical. Dead-shorting a winding on a machine tool wouldn't be a good idea either.

 

[Memmeddu]

You wouldn't need extra wires for a winding short, it must be electro-mechanical. Dead-shorting a winding on a machine tool wouldn't be a good idea either.

I'll search an example