SM74-4

I have a problem with a sm74-4 machine. When you turn on the machine, you turn the machine with a jerk and it spins but when it comes to starting it, it does not start and displays the following.
Thanks for your feedback

 

Hello you have a motor issue check with your technician maybe brushes or brake
Good luck

 

We had changed the brake but it still appears. When we put the machine under power, we can turn in step at once but turning in normal is not possible. It is the T and symbol of the motor which displays preventing the machine from turning.

 

check to make sure your brake bar handle is straight up (usually yellow) not towards the press and not away. If this is the same issue I have seen before. Could just be out of position. This will not let you idle the press but you can creep. Get it straight up and cycle the power,should fix it.

 

That error and your description means your motor brake is slipping. When you press run during the warning beeps power is applied to the motor if the brake doesn't hold the encoder detects this and that error occurs. Easy way to check is to look at the degree value while it beeps and see if it moves more than 3 deg. forward. If it does its slipping.
That test doesn't apply for inching mode.

 

Hi,we Had to change the brake but nothing. Always the same problem the machine does not start. When the machine is switched on and that one turns in jerk,it turns but in normal machine,it does not turn and lack the symbole (T) and (M). See picture above

 

Hi contractor,thank you for your intervention
Please is there no way around This.thank you very much.

 

You need to fix the problem rather than get around it.
As Four Finger Ring suggested see if the yellow brake release handle is on the wrong position - there should be a hex bolt that releases the brake if it's screwed in you will get this issue. The bolt should be free to turn with your fingers and away from the casting.
Have you checked if the press creeps forward while it beeps? You haven't answered any of these suggestions so how are we supposed to give you help.

 

Hi contractor. You were right my apologies for no return. thank you
When the machine is turned in jerks, it makes the first beep and turns, it is in jerk. on the other hand when it is to run the machine normally, the first beep is made and after the beep it rotates by some degree greater than 3 and marks the (T) and the (M)

 

So you have just proved the brake is not holding during its test. Now you have to find and fix the problem. Did you check the yellow brake release handle is not engaged via the bolt or in the wrong position? You still haven't answered this question.
Also when you say the machine turns "in jirks"
I'm guessing you mean in "inch mode"

 

I think he means after the first safety beep the press jerks and moves but (brake engages or misreads) does not start. thats exactly how it goes. When this happens , its like a reflex to go check the handle and cycle power. My water tanks are located right in front of the brake, sometimes the helper is getting dropped rags and bumps a water line etc. You explained that to him I think he just typed it again. Language barrier possibly. He needs to check the brake handle and bolt,like mentioned before.

 

Hi,FourFingerRing
I checked the yellow bar of the brake and it is free. bolt 17 is also not tight against the barti of the motor. I made movements with the yellow bar of the brake to see if it is not seized somewhere but nothing, she is quite free.

 

I am guessing the brake is applied continuously for some reason, the yellow lever should not be free, you should feel some spring resistance when you pull on it. When you inch the press do you hear the brake open? Get an electrician to check if there is continuous voltage on the brake when the press is standing.

 

thank you dear elder waqas. take the test and keep you informed. god bless you