Sorm delivery board

[abdick printer]

hi everyone

I encountered a problem Sorm delivery board would not lower automatically, when it starts to lower the overload protection disconnects. I've located the b80 micro switch mounted on the feeder board chain. when I hold it in my hand and press it the delivery board lowers without disconnecting the overload, but it would not work on its own.
Is there a conflict between the 2 boards or does the micro switch needs readjustment or replacement.

 

[junker1984]

Hey ABDick - The microswitch won't trip out the motor. By saying you can push on the board and it doesn't trip, either the board is binding or there's resistance in the pile shaft. Bearings maybe? Chains binding? Often times the brake relay starts failing and will do this, but your symptoms don't point at that. Further info and any other related symptoms might be helpful. Feel free to IM me. Steve

 

[abdick printer]

Thanks Junker
I've reviewed the maintenance manual. Step1 to check the delivery pile board limit switches. I checked those before, they were not mounted correctly, I installed them, It didn't work so I dismounted them. Surprisingly the pile board still stops at the top when inched upwards without the limit switch.
the manual also mentions (s9)electromagnet for spring preset brake (for delivery pile).

It's now working, But the motor protection switch trips all the time, press it works for a while and then trips again

 

[abdick printer]

Do you mean by "resistance in the pile shaft" that the pile board could be operated manually perfectly fine, but during printing when it is automatically inched in small increments, then it would fail?

 

[junker1984]

The reason the pile is stopping it's upward movement without the limitation switches in place, is that the safety limit switch mounted within the slow down assembly is making. my guess is the only reason you didn't wrap up the chains is because you had a pile board inserted. I suggested resistance in the pile shaft because it wasn't clear to me that the the thermal overload wasn't tripping "all the time". You'd mentioned by pushing down on the board while pushing the down button gave you positive results. Now that you mention the problem is intermittent, it seems clear that (1) there's a problem with the brake on the pile motor (2) there's a problem with either the pile motor "downward motion" contactor or brake contactor or (3) the pile motor requires servicing. Most often, in this case, it's worn contact points in the brake contactor as the 24V DC is hard on the contact points.

 

[junker1984]

I don't have schematics on hand, but a sign that there's a problem with the downward motion three phase contactor (C7 or C8?) would be carbon build up on the face of, surrounding or under the contactor. Same holds true for the brake relay (d228?).

 

[abdick printer]

Thanks a lot yes the problem is intermitant. The heavier the board the longer it works
Whenever machine stops the board won,t start oni ts own have to press the motor overload button

 

[junker1984]

Are you familiar with using a multimeter? If so, with power off, check continuity at the three phase motor contactor and the brake relay. Just in case you only know the principle of meter usage, you should know you have to remove one wire of each side and tighten the lug down to get a true reading. Might be best to bring in a qualified tech or electrician if you're unsure of procedure.

 

[abdick printer]

Hi Junker
I got hold of a qualified electrician but with average experience.
We found that the b81 micro switch mounted on the feeder chain is working fine, it signals to the c8 contactor
to lower delivery pile board automatically and the board starts to lower.

when inspecting the b80 limit switch with the wheel mounted on a toothed plastic disc located under the lower
lower cover on the operator side- the disc is connected to a shaft rotated by the pile motor- we found that when the wheel is on the low contour of the disc, the pile board lowers
automatically but when the limit switch wheel gets to the high contour it causes the motor protection switch to
disconnect.

the electrician suggested that there is a conflict (timing issue) between the two switches caused by one of them
lagging behind the other for some reason.

but we don't know what is the b80 limit switch used for and how to set the timing other than by trial and error.
we plan to continue work tomorrow, Any suggestions welcomed

 

[junker1984]

No timing issue between the two switches. The roller switch on the star cam simply breaks the self holding circuit that lowers the delivery on command from the feeder governor foot. Are you certain it's not just a coincidence that the motor protection tripped at the high lobe of the star cam? Certainly, that switch is only in the control circuitry, wouldn't have any direct tie in to the three phase motor circuit.

 

[junker1984]

I read, and reread, your post...it took a bit for my feeble mind to click! I had first taken your explanation that the protection only tripped on the high lobe. Keep in mind when looking at this next, when the motor is commanded to lower, it will only, when working properly, travel from "low contour" to "high contour". Then, when the motor is commanded to lower next, it will only travel from "high contour" to "low contour". And so on and so forth. This really does sound like a bad contactor (best case) or a motor or brake issue (worst case). Do yourself a favor and have your electrician ohm out the motor "down" contactor's contact points.

 

[abdick printer]

Thanks junker
So the function of the micro switch moiunted on the feeder
chain is to lower the delivery pile board
And the limit switch on the star wheel stops the pile
Board at certain increments

 

[junker1984]

Yes

 

[abdick printer]

Little improvement achieved today.the delivery pile board lowers
Automatically but it needs to be lowered manually every 20 minutes
Or so otherwise the automatic will stop completely but the overload
Switch doesn't disconnect. Just played around with the switches
Mentioned earlier plus the feeder head mico switched. Next run
Due in 2 days

 

[junker1984]

If you moved the micro switch that reads the chain movement on the feeder pile, you'll probably find that it needs to be readjusted. On an average thickness stock, .1 to .2 mm, the delivery should lower about every 6 times the feeder raises.