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HLV-H With a Noisy Brake Solenoid

crpearson

Plastic
Joined
Apr 23, 2017
Location
Santa Cruz
Good evening Gentlemen... I just got myself a new HLV-H that has a really noisy brake solenoid. The brake mechanism works perfectly, but when the lathe is running and the brake is retracted, it makes an awful buzzing noise. Just wondering any of you Hardinge gurus out there have seen this before and can get me going in the right direction?

My guess is that the solenoid is not getting quite enough power and I have a dirty relay somewhere. I was planning to really dig into it tomorrow and I thought I'd try to learn from your experience if possible. Thanks as always for any thoughts or help you can share with me.

Cliff
 
My HLV one was doing this until I cleaned the faces that come together when it pulls in, with some emery wrapped around a flat file.
 
Mine does not make any audible noise above the machine level noise.

It should be simple to remove the back grill/cover and then remove the brake cover. Then turn the machine on and it should be clear what is loose.
I don't use the brake. I cup my fingers around the inside of the hand wheel.
 
Common problem.

there are copper wire loops through the lamination of the armature. Their job is to add a phase shift to the alternating magnetic field and thus prevent it collapsing when the current reverses.

You will find there is a crack/ fracture in the loop(s) . Simple fix is to soft solder the crack , a better fix is to re-weld them (which is anneal them and make them last another few years)

bill
 
Thanks guys for your thoughts. This is an old-style machine with the solenoid in the back. I tore the entire thing down and discovered the bolts that should have been holding the solenoid in place were both sheared and the solenoid was very loose in there. I went over everything with a file toothed comb, cleaning and inspecting everything and went out and got some new bolts. I put it back together, but that still didn't solve the problem...

At least when the spring is installed. Without the spring installed, the solenoid makes no noise, but even slight downward pressure on the lever causes it to start buzzing like mad. Here are the things I've checked:

- No cracks in the armature (visually anyhow)
- Cleaned everything carefully
- Repaired the mounting system
- Tested line voltage both under load and not. It's 230.

Any thoughts?

Thanks,
Cliff

IMG_1983.jpg
 
The top end of the lamination stack has what looks like holes on each end. Should there not be a bolt with nut in each of those two holes? These are the two holes
directly below the 45 degree cut in the lamination plates.

Or are the laminations held together with rivets?

A simple thing to try is attach two small C clamps on those two locations I mentioned and see if that reduces the chatter.

Otherwise I would trust the Billtodd recommendation.
 
Good eye!!! I checked that out and as far as I can tell those homes have never seen a bolt. They seem to be welded or otherwise bonded together. I clamped them and the noise continued.

The total resistance in that coil is 43 Ohms. I’m no electrical engineer, but that seems reasonable to me.

Here are some photos. I polished the contact points a bit but I’d anything it made the noise worse.

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Sent from my iPhone using Tapatalk Pro
 
Are you aware you can buy a brand new one for $135 and be done with your buzzing contactor forever. Your pictures show a unit that is completely worn out.

Stuart
 
repair the copper loops in the moving part.

Thank you Bill! I don't see any copper loops at all in the plunger. Are you referring to the copper loops in the part below? I didn't see it at first, but there actually is a very small crack in one of those loops on the corner. I will weld it up tonight. Thank you again for your help!

Stewart, I would probably buy a replacement at that price. I was under the impression they were a good deal more expensive. I saw someone who was quoted almost $600 from Hardinge. Would you mind sharing your source with me?

Thanks guys!

IMG_2001 copy.jpg
 
It is probably just the laminations vibrating in the "iron" cores. I would think a wicking grade Loctite would get between the laminations and keep them from vibrating. After applying the Loctite put it in an oven at 200F for an hour to set the Loctite so it does not get into any moving parts.
Or just ignore it, it is not hurting anything.
 
I may have led you astray..I went back to the web site I had found that listed that GE solenoid and realized the $135 was for the coil ONLY..oops!

Regardless, here is the link, maybe they can be some help finding a repair part. Sorry for the false lead.

Industrial Solenoids |GE Renewal Parts from PSC

Stuart

No problem. Actually that link was quite useful as I called them and they can supply a complete solenoid. That's the good news... Bad news is it's an 18 week lead time with a $475 bill. Thank you for the link to that other thread. I will investigate going that route.
 
It is probably just the laminations vibrating in the "iron" cores. I would think a wicking grade Loctite would get between the laminations and keep them from vibrating. After applying the Loctite put it in an oven at 200F for an hour to set the Loctite so it does not get into any moving parts.
Or just ignore it, it is not hurting anything.

That's an interesting idea. If all else fails and I wind up ordering a new part, I will give that a try. Thanks for the idea!
 

Something dented the corner (upper left) in first pic. How the copper ring got damaged can be to mishandling or use. Why would the shape be altered so much in normal operation?

Your text said that to fix you would weld the ring. On or off the metal lamination stack?

I am not sure how it is done on a machine. But my thought would be to get a length of copper wire and possibly file it down to square cross section.
Then bend it around the form it is to be installed on. Then remove the wire and solder or braze the ends together. Press the ring on the stack.
 
I suspect that the damage was caused by the broken bolts. When I got the machine both bolts that hold the solenoid in place were sheared off and the device was flopping around inside its housing. I suspect it engaged at a strange angle and the strike from the plunger deformed the copper loop, cracking it.

To test the fix I soft soldered a copper wire bridge between the two corners of the loop. I'd planned to weld it had it worked. I could remove the loop and attempt to form new ones. The do not appear to be appreciably insulated from the laminations in any way.
 
Your post got me looking at my brake. You know when it has been a while since you last checked stuff when there are cob-webs inside the cabinet.
It was not adjusted so I fixed that.

I ran the lathe with and without brake stopping. My observation is that the brake is going to save a little time when running in the high speed range, like over 1000 RPM. Otherwise it's just a second or two.

When the brake is in use the cork will engage the motor flywheel when the spindle is stopped. This prevents the operator from rotating the hand wheel. But I will often rotate and measure when I am creeping up on a dimension.

Tip: I had coated the threads on the round adjustment nut with some gray anti-sieze paste. I do not regret that.
 








 
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