1988 GTOZ Main Motor Hum

Hi everyone,

We own a 1988 GTOZ 52. Recently, the overall tone/signature of the noise the press makes has changed. Most notably, it appears that the hum/noise that the main motor makes has changed to a one that is heavier than usual.

I am not the person operating the press, but I am trying to assist in figuring out what might be wrong with it. I took off what appeared to be an inspection cover from the housing of the main motor (the one with the vent grills on it) to inspect the motor. From the limited view that I had, I couldn't see anything terribly wrong with the motor's winding's (the enamel on the windings wasn't discolored, the brushes and the grooves that they ride on seemed OK as well).

My best bet would be that there is a bearing that is about to go out? I was hoping someone who has some hands-on experience with the press would be able to point me in the right direction.

Is there anything like e.g., a service manual for the press that I could take a look at?

Thanks in advance.

 

There has never been issued a service manual for main drives on any HDM machines. Operator manual suggests a once yearly inspection of motor by competent electrician. Brushes on slip ring (pulley/right) side and commutator (brake/left) side require replacement upon reaching a certain wear length. It would be to
your benefit to remove motor and send to motor shop for a complete servicing. I understand the expense may be intimidating, but the machine cannot make you money if the motor burns up due to a seized bearing, over amp situation from excessively worn brushes or a faulty brake assembly (those three items would likely be the culprit causing the noise you’re hearing). Also, don’t discount the possibility of a worn out drive belt or a bad bearing in the auxiliary pulley/shaft/flywheel assembly located gear side of first unit lower main frame.

 

You will need a long ~400-600mm screwdriver and a lot of CAUTION! alternatively, you can use a rod or threaded rod attached to it with a tin lid from a small glass jar (50mm in diameter). Carefully put the metal end of the screwdriver as close as possible to the bearing and rotate the engine, lean the screwdriver handles against your ear, this will transmit and amplify the sound of a suspicious bearing.
The bearing on the side of the drive belts starts to make noise first, it is the most loaded.
I can advise on repairs at home.
The result will depend only on your manual skills and the availability of the necessary tools.
For operational diagnostics, we bought the following device:

images.app.goo.gl/9G6Eu4wdQp9DoWCF9

 

Hi sir

Time of maintenance of Main Motor, according to the International Regulations of IEEE, every year, must be done.

Good luck.

 

Hello again,

Apologies for the late reply, I was out of town for the last couple of days.

A little background info on the machine - it was bought second hand from a shop that closed down approx. 12 years ago. Before that, the shop that closed down had bought it from a reputable local 2nd hand Heidelberg dealer, which inspected the machine and replaced anything that needed replacing, I assume. We never run it really hard (most of the time it runs at 3,000-4,000 items/h), but that won't stop anything that is going to break from breaking.

The service manual suggestion was really because I service digital presses, so my mondus operandi is basically look up any relevant information on the service manual or any other documentation like technical bulletins issued by the press' manufacturer. Unfortunately, all the documentation for our GTOZ that we have is in German, which makes life a little difficult.

My goal right now is to try to perform as many diagnostic tests as possible in order to narrow it down to 1 or 2 suspect parts and maybe try and replace it ourselves, if possible. Can you advise me on how to proceed with narrowing the list of suspects down?

I don't really remember exactly how the inside of the motor looked like, but - and that is if I remember correctly - there didn't seem to have easy access to its bearings? I will order one of those inspection stethoscopes that you posted - it will be a useful tool either way.

 

@orestes
I have paper documentation for the GTO 52, in German))) This is the spare parts catalogue: Edition 02/02 - 00.999.5132/03
The main electric motors in it are drawn correctly, signed "V-belt")))
If you don't mind, post a photo of your engine to get an idea of the scope of the disassembly work.
The difference in the repair of the motor of a single-color and five-color machine is very large.

 

You’ve not mentioned if you did a thorough job of checking possible causes of the vibration on drive sub assemblies outside of the motor. Belts (2 of them), pulley, flywheel and belt tensioner.

 

It is a 2 color machine, what photos would you like?

Hi junker,

I haven't done anything yet. I can only see one flat belt running from the main motor, underneath the feed table, to approx. to the middle of the machine. Where would the 2nd belt be located? All the parts you mention seem to be somewhere within the machine and unfortunately I have no idea to where the general location of each part is - is there some short of diagram I can consult?

 

In all honesty, I believe you’re in over your head.

 

@orestes
Remove the gallery and shroud on the drive side. you will see the main motor, belt, main drive pulley.
Take a sheet of paper, roll it into a cone with the pointed end open, and listen to the machine as it spins. This will help localize the noisiest places.

 

Hi sir
Time of maintenance of Main Motor, according to the International Regulations of IEEE, every year, must be done.

 

Hello,

Main drive belt (from the motor to the 1st pulley) is alright - no cracks or missing pieces. Same goes for the belt that drives the flywheel on the side of the machine. Inspected the brushes, they seem to have some life left in them but I am not sure if the remaining amount is within spec.

How can I disassemble the motor in order to access the front 6206 bearing near the drive pulley of the motor? Looking around the motor there really doesn't seem to be a straightforward way. The front housing of the motor seems to be held into place by some hidden bolts that it seems like they aren't accessible from the outside.

Brushes: https://imgur.com/a/oBppjKu

imgur.com/0iScb7o

 

Here you go: https://imgur.com/kVELN8Q

 

Take the motor,,
To some specialist.

Blessings

 

@orestes

Are you qualified? YES- see point 1) NO - see point 9)

1) disconnect the wires (mark the numbers, take a high-quality photo)
2) dismantle the engine
3) put a copper coin or mild steel between the puller and the shaft, lubricate
4) remove the pulley with a puller (heat the pulley before removing it to 100 degrees Celsius with an electric air heater)
5) disassemble the brake side (brake, brushes, brush holder, brush side housing)
6) remove the cooling grilles, unscrew the thrust washer on the pulley side, unscrew the crankcase on the pulley side.
7) now you can change bearings and grind lamellas
8) IMPORTANT! bearings must be with increased thermal clearance and heat-resistant grease!

9) Say "Why do I have a headache?" Pour yourself a drink and find an electric motor repair shop that gives a warranty on repairs.