What did you buy today? Post your latest purchase!

[cat87]

An almost unused Keithley 199 dmm and a Wayne-Kerr 4210 LCR bridge.

And if you want to know about the barbaric wiring on the Wayne-Kerr...yeah,  I did that. The old posts were shot so I bodged them quick and dirty

[CJay]

These are for disassembling the big old 3-phase motor that came with my recently bought large lathe. I can't start on refurbishing the lathe yet, but I do have space to do the motor. It was made in the early 1950s, and looks like something out of a 1920s Amazing Stories (early SciFi) magazine illustration.

Wow, that motor...

The company Lancashire Dynamo and Crypto were only about 8 miles from where I live now, my first job was through GEC who took them over and eventually closed therm down but there's still a subsidiary of theirs doing business, Crypton, the automotive diagnostics people.

A bit of history here:

https://www.gracesguide.co.uk/Lancashire_Dynamo_and_Crypto

[capt bullshot]

Edit to add: The plate says the motor is Y-wound, and there is no Neutral. Any one know if this is a problem for variable frequency drives?

That's pretty normal and shall work with an VFD. But I won't recommend doing so: The high dU/dt at the VFD's output might kill these old windings, the isolation material isn't made to cope with that and may break down over time. If you want to use a VFD with such an old motor, I'd recommend a sine filter (placed between VFD and motor).

[vk6zgo]

Open frame (ventilated) 6 pole, yeah they made them big back then.

Interestingly, that sheet metal mesh outside around the end vents, is spotwelded to the cast iron endpiece. I didn't know that was possible.

Gunna spigot the 2 socket parts THz ?
That'd keep alignment good and it looks better too.....like you know what you're doing. 

If I knew what I was doing, I'd probably know what you meant by 'spigot'. 
Do you mean cut a lip in the faces on a lathe, to center the extension tube accurately? And chamfer the weld seams? I will be doing that. Just haven't found/bought a suitable bit of tube yet, so don't know dimensions.
Alignment will be by clamping the parts in a bit of L section.

In the motor, the windings/pole piece seems to be fixed in the frame solely by heat-expanding the frame onto it. I think I need to separate them for a few reasons, so heating the frame up (without wrecking the old windings) will be a bit nail-biting.

Edit to add: The plate says the motor is Y-wound, and there is no Neutral. Any one know if this is a problem for variable frequency drives?

Btw, did anyone else catch that company name on the brass plaque?
"Lancashire Dynamo & Crypto Ltd England"

It also says that individual motor was built in Oz by Nilsens.
They used to be big in all sorts of industrial electrical stuff--- we used to sell their battery chargers at my first job, & I saw a lot of their gear during the early part of my later technical career.

The very look of that motor takes me back---- a lot of the motors I ran into over the years would have been of a similar vintage.
They were pretty much unkillable, but if you did, there were motor rebuilders who could pull them apart & fix them, giving you another 20 years!

There still might be one or two of those Electrical Fitter/rebuilders around, who can give you some tips.

[Specmaster]

Open frame (ventilated) 6 pole, yeah they made them big back then.

Interestingly, that sheet metal mesh outside around the end vents, is spotwelded to the cast iron endpiece. I didn't know that was possible.

Gunna spigot the 2 socket parts THz ?
That'd keep alignment good and it looks better too.....like you know what you're doing. 

If I knew what I was doing, I'd probably know what you meant by 'spigot'. 
Do you mean cut a lip in the faces on a lathe, to center the extension tube accurately? And chamfer the weld seams? I will be doing that. Just haven't found/bought a suitable bit of tube yet, so don't know dimensions.
Alignment will be by clamping the parts in a bit of L section.

In the motor, the windings/pole piece seems to be fixed in the frame solely by heat-expanding the frame onto it. I think I need to separate them for a few reasons, so heating the frame up (without wrecking the old windings) will be a bit nail-biting.

Edit to add: The plate says the motor is Y-wound, and there is no Neutral. Any one know if this is a problem for variable frequency drives?

Btw, did anyone else catch that company name on the brass plaque?
"Lancashire Dynamo & Crypto Ltd England"

It also says that individual motor was built in Oz by Nilsens.
They used to be big in all sorts of industrial electrical stuff--- we used to sell their battery chargers at my first job, & I saw a lot of their gear during the early part of my later technical career.

The very look of that motor takes me back---- a lot of the motors I ran into over the years would have been of a similar vintage.
They were pretty much unkillable, but if you did, there were motor rebuilders who could pull them apart & fix them, giving you another 20 years!

There still might be one or two of those Electrical Fitter/rebuilders around, who can give you some tips.

There are loads of motor rewinders around who will rebuild the motor including new bearings fitted as part of the service.

[TerraHertz]

Being cast, it's not like it will rust away anytime soon like if it was steel. Hit it carefully with a flap wheel or a cup brush, smear some grease on the brass plaque and slop/spray some paint for decoration on as like I said cast ain't gunna rust away anytime soon.

Rust is not the problem, it's the thick multiple coats of paint flaking off, same as on the lathe. With plenty of concave nooks, so forget flapper wheels. Plus wanting to get a painted finish on the motor consistent with the lathe. The lathe paint-removal will be a big job and WILL involve sand blasting. So, the motor too.
I took the motor frame to a motor rewinding place today, and asked advice about separating the frame and field assembly. Their opinion: forget it. Much harder than you'd expect. Better to sand blast with the windings in place, but protected with something.

Then driving home I found a roll of old thick carpet on the kerb, so that's my first choice of a protective layer.
That leaves the problem of getting the nameplate pins out. I think that won't be too hard.

For the socket tube, another thought.....diff axle tubes can be fairly thick wall tube if you have some of that sort of scrap lying about.

Heh. There's not many kinds of scrap I don't have lying around. Yep, a couple of transmission shafts. But they are spares for my Subaru. What I'm using is a section cut from an exercise treadmill belt roller. Pretty much ideal.

The plate says the motor is Y-wound, and there is no Neutral. Any one know if this is a problem for variable frequency drives?

That's pretty normal and shall work with an VFD. But I won't recommend doing so: The high dU/dt at the VFD's output might kill these old windings, the isolation material isn't made to cope with that and may break down over time. If you want to use a VFD with such an old motor, I'd recommend a sine filter (placed between VFD and motor).

Oh. Good point. Never having used a VFD before, I had assumed they'd all (mostly?) use HF chopping with a filter, for reasonably sine-like outputs. Are there any like that?

[Specmaster]

Being cast, it's not like it will rust away anytime soon like if it was steel. Hit it carefully with a flap wheel or a cup brush, smear some grease on the brass plaque and slop/spray some paint for decoration on as like I said cast ain't gunna rust away anytime soon.

Rust is not the problem, it's the thick multiple coats of paint flaking off, same as on the lathe. With plenty of concave nooks, so forget flapper wheels. Plus wanting to get a painted finish on the motor consistent with the lathe. The lathe paint-removal will be a big job and WILL involve sand blasting. So, the motor too.
I took the motor frame to a motor rewinding place today, and asked advice about separating the frame and field assembly. Their opinion: forget it. Much harder than you'd expect. Better to sand blast with the windings in place, but protected with something.

Then driving home I found a roll of old thick carpet on the kerb, so that's my first choice of a protective layer.
That leaves the problem of getting the nameplate pins out. I think that won't be too hard.

For the socket tube, another thought.....diff axle tubes can be fairly thick wall tube if you have some of that sort of scrap lying about.

The plate says the motor is Y-wound, and there is no Neutral. Any one know if this is a problem for variable frequency drives?

That's pretty normal and shall work with an VFD. But I won't recommend doing so: The high dU/dt at the VFD's output might kill these old windings, the isolation material isn't made to cope with that and may break down over time. If you want to use a VFD with such an old motor, I'd recommend a sine filter (placed between VFD and motor).

Oh. Good point. Never having used a VFD before, I had assumed they'd all (mostly?) use HF chopping with a filter, for reasonably sine-like outputs. Are there any like that?

I think I would forget about sandblasting the motor as being to risky. Leave the brass plate in situ and just some good old fashioned paint stripper. Much safer and possibly less cost as well.

[tautech]

Then driving home I found a roll of old thick carpet on the kerb, so that's my first choice of a protective layer.
That leaves the problem of getting the nameplate pins out. I think that won't be too hard.

Great, the carpet should help protect the lathe bed when you get onto doing that.
The plaque pins, are you sure they're not screws with their slots full of paint ?

For the socket tube, another thought.....diff axle tubes can be fairly thick wall tube if you have some of that sort of scrap lying about.

Heh. There's not many kinds of scrap I don't have lying around. Yep, a couple of transmission shafts. But they are spares for my Subaru. What I'm using is a section cut from an exercise treadmill belt roller. Pretty much ideal.

Will you turn a step (spigot) on the 2 socket pieces for the tubing ?

[capt bullshot]

Oh. Good point. Never having used a VFD before, I had assumed they'd all (mostly?) use HF chopping with a filter, for reasonably sine-like outputs. Are there any like that?

You're right with the "HF" chopping (they use frequencies in the 4kHz to 16kHz range), but there's no filter inside. They output the raw PWM square wave and use the motor as the filter. Sine wave filters are optional, you'll have to supply them.

[TerraHertz]

Great, the carpet should help protect the lathe bed when you get onto doing that.
The plaque pins, are you sure they're not screws with their slots full of paint ?

Heh heh, do you think I'd point a sandblaster at a lathe, without first protecting all the precision surfaces?
Yes, the roll of carpet will be useful.

Those pins - nameplate fasteners are virtually always hammer-in pins. Very hard steel, with spiral flutes that cut into the base metal. The pin heads are deliberately featureless domes, to make them impossible to grip. The best way to get them out is with a pin punch from the other side, if the holes go all the way through.
Turns out the holes on this motor frame don't go all the way through, so that left the fallback methods:
1. Grind small flats on opposite sides of the head, to give something for vicegrips to grab. Then pulling and turning at the same time, they unscrew. But this way the pins lose their original appearance.
2. If you want to not damage the pins, so they can be reused: Cold chisel with a sharp cutting edge. Put the edge where the pin head rests on the plaque, tap sharply with hammer. Trying not to dink the soft brass plaque, while working round the head of the pin. The idea is to loosen the pin in the hole, and also work it out a tiny bit. That tiny bit gives vicegrips a lip to grab, and then you can twist the pin out.

Anyway, they're out now. See pic. Very minimal damage to the plaques. One pin head was already partly sheared off, I think from when it was initially hammered in. I got the stub out, fortunately.

Will you turn a step (spigot) on the 2 socket pieces for the tubing ?

More like a groove, to position the tube. I'll run a bolt through the middle of the set to keep them tight, while it's in the pipe welder thingy (a rough improvisation from a while back.) The steel of the impact socket really doesn't like machining with a silversteel cutting bit. Have to dig out some tungsten bits.

[tautech]

Nice work THz. 
Gunna tap the hole out for some better looking brass screws ? 

Yeah I wondered how you'd get on turning impact sockets. 
Like you I only drag out the tungsten for 'special' jobs. 

[TerraHertz]

Gunna tap the hole out for some better looking brass screws ? 

Nope. With really old things I like to maintain historical accuracy. In another 60 years or so, the next person refurbishing this lathe may wish to put in newfangled brass screws.

What I'm really torn about, is whether to use boring gray paint (per 1950s original) or something a little more cheerful. I think the latter.

Yeah I wondered how you'd get on turning impact sockets. 

I was surprised actually. To do anything with the impact socket parts I'd half expected to have to use grinding in the lathe. Something I prefer to avoid, since the grit gets into the ways.
But actually they are not extremely hard. Silversteel bits do cut it. Just with a high wear rate, and only shallow cuts.
Maybe I'll still do the grooves with a plain cutting bit. They can be very shallow.

[tautech]

Gunna tap the hole out for some better looking brass screws ? 

Nope. With really old things I like to maintain historical accuracy. In another 60 years or so, the next person refurbishing this lathe may wish to put in newfangled brass screws.

What I'm really torn about, is whether to use boring gray paint (per 1950s original) or something a little more cheerful. I think the latter.

Nipple pink or breast flesh white ? 

I'll get my hat and run................

[TerraHertz]

Nipple pink or breast flesh white ? 

Hello Kitty, anime waifu, or Tank Girls theme? It's a difficult choice.


At 1:58 - Create your own original tank with customization

But no. I think cottage green, or one of the other hard-setting enamels.

[vk6zgo]

Gunna tap the hole out for some better looking brass screws ? 

Nope. With really old things I like to maintain historical accuracy. In another 60 years or so, the next person refurbishing this lathe may wish to put in newfangled brass screws.

What I'm really torn about, is whether to use boring gray paint (per 1950s original) or something a little more cheerful. I think the latter.

Yeah I wondered how you'd get on turning impact sockets. 

I was surprised actually. To do anything with the impact socket parts I'd half expected to have to use grinding in the lathe. Something I prefer to avoid, since the grit gets into the ways.
But actually they are not extremely hard. Silversteel bits do cut it. Just with a high wear rate, and only shallow cuts.
Maybe I'll still do the grooves with a plain cutting bit. They can be very shallow.

I guess if it is still in the original paint, you know it  :popcorn:has probably never been rebuilt.
Motor rewinders used to have a fetish for slathering everything with blue Hammertex paint.

[TerraHertz]

Motor rewinders used to have a fetish for slathering everything with blue Hammertex paint.

You have a problem with blue hammertex paint?

(Pic is the last motor I prettied up, from an old vacuum pump. I happen to have a box full of tins of hammertone blue paint. A freebie. No, I'm not using it on the lathe.)

[Towger]

good old fashioned paint stripper.

The key words are 'old fashioned'.  The modern stuff here is useless.  I bought a large can of Nitromors in Homebase (Bunnings before they offloaded it) a few months ago.  It was useless, did not even touch the surface of the 1960s metal paint on aluminium parts.
I ended up sending the parts off the be professionally striped.   
According to the striper they changed the formula about 15 years ago, removing the 'good stuff'.  It certainly did not smell as strong as I remember.

[Mr. Scram]

The key words are 'old fashioned'.  The modern stuff here is useless.  I bought a large can of Nitromors in Homebase (Bunnings before they offloaded it) a few months ago.  It was useless, did not even touch the surface of the 1960s metal paint on aluminium parts.
I ended up sending the parts off the be professionally striped.   
According to the striper they changed the formula about 15 years ago, removing the 'good stuff'.  It certainly did not smell as strong as I remember.

There's a lot of that going on. It's probably for the best, but sometimes you yearn for the good stuff that kills at least three whales upon opening the can.

[AF6LJ]

California is really bad about restricting everything.
This state is turning into Cuba West, you can't get any good affordable paints here anymore and don't even think about getting anything stronger than acetone, they would ban that if they could get away with it.

[jmelson]

Oh. Good point. Never having used a VFD before, I had assumed they'd all (mostly?) use HF chopping with a filter, for reasonably sine-like outputs. Are there any like that?

Nope, they all put ~400 V square waves into the motor, with pretty sharp edges.  Most 230/460 V motors handle this pretty well.  If the motor was specifically wound with insulation only good for 230 V or so, that could be a problem.

You can add series inductors on the motor side of the VFD to round off the sharp edges.

Jon

[innkeeper]

look what popped up at my local surplus / salvage place....
it was a fun afternoon repair project with my son.
after replacing the 1/4" speaker jack, resoldering two cracked solder joints in the rf area coming from the bandswitch, and switch and potentiometer cleaning, and its on his desk picking up WWV on 20 ft of wire

[Specmaster]

nice receiver.

[AF6LJ]

I had one of those for a short time when I was in my mod teens, I horse traded to get it and horse traded it away a month later. Wish I had not, it was a fun radio.

[Cubdriver]

California is really bad about restricting everything.
This state is turning into Cuba West, you can't get any good affordable paints here anymore and don't even think about getting anything stronger than acetone, they would ban that if they could get away with it.

Yeah, California is cuckoo-nuts in that regard.  McMaster can't even ship friggin' low VOC electronic grade RTV silicone to my company out there.   

-Pat

[Kjelt]

An extra Bernstein clamp/helping hand, this time chose an ESD safe version