Geared Motor Overload Setting

They are right.

That doesn't mean the overload can't be reset.

It means that the motor may be too big for the application.

This appears a good application for a torque limiting clutch between the motor and the belt drive At least one clutch make that I know of, Mayr (mayr.com) has provisions for a limit switch to be mounted on the clutch to indicate that the clutch has released, and could be used to shut off the motor.

They are wrong. A lower overload setting provides even more overload protection. However, if the overloads are set low enough to catch the belt stoppages, they may trip when starting the motor. Your plan is worth a try, at least.

The slip clutch is a good idea. Yet another possibility is to increase the belt tension, unless already excessive.

Hi Vulcan,

It is an interesting problem. Yes, it is easier to monitor the belt temperature. Can you tell me the normal belt operating temperature range and the upper limit at which you need to trip the motor circuit?

You need to ask why the belts won't transmit the available power from the motor. If they were in large enough section and sufficient in number to transmit full power will something else break? If not then you will be able increase production with the full power transmission capability afforded by a properly engineered belt drive.
Jim

The primary reason of an overload is to protect the motor, If you set this value below than the FLA you are still going to protect the motor and maybe the cheapest way to sort your problem.

Other than a shock relay, an underspeed sensor can be used for slippage.

Dear Mr. Vulcan,

The over load relay is meant for the Protection for the Motor. If you reset the relay for lower over current current value, it will work. But that is not the only solution.

In your case, I am of the opinion that:

1. There is a mis-match between the motor power required and installed.

2. The selection of the belt that are used needs a re-look interms of belt SELECTION CRITERIA, and use correct size and number of belts.

3. The equipement tripping indicates the shock load is more than design value - which results in slippage of belt, thereby heat generation in the belt and burns out.

Pl. get the above points checked and inform this forum, what was the problem identified, and solved.

DHAYANANDHAN.S

I read the post and found it to be educational. I thought I would throw out an idea, if its impractical, please let me know. Would it be possible to install some type of optical sensor on the motors gear drive, that way the motor would shutdown before it got hot enough to trip a thermal sensor ?

Thermal sensor for motors is usually installed within motor winding. For external sensing you can use infrared temperature sensor with trip temperature control switch to trip the motor. There are many types of IR sensors you may find on www.omega.com/

I would install a "zero-speed" or a "belt-slip" detection switch on the belt end opposite the drive input to monitor the belt speed.

Once the switch is installed in series with the stop-start control circuit you need only start the belt, run it at rated load, and set the switch to interrupt the conveyor control any/every time the belt ceases to reach and maintain correct operating speed.

The switch will require preventative maintenance on a regular schedule.

There are several companies such as TURCK, Conveyor Dynamics, that offer this type of switch complete with installation and calibration information.

Hi guys, 'got a little busy these past days.
Yeah, the idea might result in nuisance trips on start up. I'll have to have someone check on the starting current. Thanks everyone!

regards,

Vulcan