Relating to "Noticing a Belt"

[ptonsparky]

30 HP with VFD. First trouble with it was belts slipping. Second was a broken paddle locking up the chain. Now, the third was a belt that came off leaving two, which is insufficient to handle the load. Unfortunately the slipping drive belts and locked chain result in a similar reaction. I had the current limit set to 50 amps which did shut things down with the broken paddle, but it also shuts things down as the belts slip then grab, slip/grab, making the operator think broken paddle again. Increasing the current limit to 70 amps squealed the remaining two belts, but just added to the suspicion of broken paddle. The belts are 20' feet up and require a lift to get to. Eventually the belt problem was found and stairs are now in the works for access to the belts, along with 4 belt sheaves.

Question now is 50 amp current limit or leave at 70 amp plus?

 

[Fulthrotl]

30 HP with VFD. First trouble with it was belts slipping. Second was a broken paddle locking up the chain. Now, the third was a belt that came off leaving two, which is insufficient to handle the load. Unfortunately the slipping drive belts and locked chain result in a similar reaction. I had the current limit set to 50 amps which did shut things down with the broken paddle, but it also shuts things down as the belts slip then grab, slip/grab, making the operator think broken paddle again. Increasing the current limit to 70 amps squealed the remaining two belts, but just added to the suspicion of broken paddle. The belts are 20' feet up and require a lift to get to. Eventually the belt problem was found and stairs are now in the works for access to the belts, along with 4 belt sheaves.

Question now is 50 amp current limit or leave at 70 amp plus?

50 amps. 30hp @ 460 is 46 amps on my little motor app.

if you leave it at 70+ when something goes amiss, you'll probably smoke the motor.
then you can use the stairs to get up there to pull the motor.

4 sheaves will probably solve that problem... in the meantime, put three new belts on,
and spray them liberally with belt dressing so they hook up.

 

[ptonsparky]

50 amps. 30hp @ 460 is 46 amps on my little motor app.

if you leave it at 70+ when something goes amiss, you'll probably smoke the motor.
then you can use the stairs to get up there to pull the motor.

4 sheaves will probably solve that problem... in the meantime, put three new belts on,
and spray them liberally with belt dressing so they hook up.

Out thoughts were "At least something will be noticeably broken."

Hopefully the overload kicks in before the motor smokes.

 

[gar]

150529-1002 EDT

ptonsparky:

As in earlier discussions about one of your projects I had suggested a power monitor. A power monitor might be useful here.

To solve short time peak overloads integrate the power over some suitable time period like 5 seconds and use this 5 second value and a threshold near the motor's full load power rating, or thereabouts. Use a highrer threshold on the instantaneous power.

.

 

[ptonsparky]

150529-1002 EDT

ptonsparky:

As in earlier discussions about one of your projects I had suggested a power monitor. A power monitor might be useful here.

To solve short time peak overloads integrate the power over some suitable time period like 5 seconds and use this 5 second value and a threshold near the motor's full load power rating, or thereabouts. Use a highrer threshold on the instantaneous power.

.

The frustration alone could warrant the power monitor.

The drive does, or can, give me alarms on power. We had used it in the past when it was set up on an auger that could be overloaded by the amount of corn fed to it.


The system now can not be overloaded with product alone. Why the 50 amp current level was selected, right or wrong.