Chain Conveyor

Chain drives work best if the motor is "pulling" the loaded side, keeping tension on the side of the chain that is doing the work. With the motor located on the bottom of the run, the chain tension will be on the non-working run of the chain.

You will in effect be trying to "push" the chain up the incline.

I'm not saying it can't be done, but I don't think it's done very often.

If the motor is at the top it pulls the load on the ascending chain branch the descending chain is not loaded (only by the own weight ). If the motor is at the bottom the FULL chain is loaded since you pull up the load via the descending chain branch ! The wear will be more intensive since the chain is loaded full time and with the motor at top only half time. Placed at the bottom the motor will lead to a higher maintenance cost due to a more frequent replacement of bushings and other wear chain parts. More than that the bearings of the upper sprocket shaft will be loaded 2x as much as with motor at top their life expectancy could drastically decrease if they are able to support the increased load at all.

If you have a lot of money and do not mind if repair times are going up move the motor down.

In addition to the reasons given in posts 1&2, it seems like installing some type of heat shield & fan would be less expensive than reinventing your conveyor.

I would look into using regular chain link (like motorcycle chain) to drive the conveyor. It's just a matter of putting a sprocket on the top shaft and keeping the new chain out of mischief with proper guards. Use a large sprocket to reduce wear.

Now your motor is down where you can keep an eye on it, shorter electrical leads.

If possible, upgrade the upper bearings. Double Timken roller bearings are my favorite, will mount right in where ball bearings were.

Hi, rosli,

You state that your concern is with the motor cable burning and tripping of the motor. You want to move the motor to the ground floor for better monitoring and control.

This is not clear. Is your problem that the motor cables are burning because of the boiler heat causing fires or because they are too small to carry the current the motor requires to operate? If you have tripping of the motor you are suggesting that the cables may be too small or the motor does not have enough power to do the job.

Do you want to move the motor because it is in a bad location where heat/dust/fire hazard/access problems are causing excessive maintenance?

Chain conveyors can be driven from nearly anywhere along their length but there are engineering issues you must be aware of before you proceed to make the changes. I am assuming your existing conveyor is driven by the head sprocket at the top of the conveyor and has a tail idler at the bottom of the conveyor.

The best way to do this is to install an "S-drive" into the chain return at the point where you want to put the drive. The S-drive consists of two chain sprockets, arranged so the chain returning from the top of the conveyor wraps 180 degrees around the new driving sprocket. It then runs over a second idler sprocket which turns the chain 180 degrees so it is aiming at the conveyor tail idler. Your conveyor chain must be built so it can be flexed both ways over a sprocket. It cannot have chain attachments that will interfere with the sprocket when flexed "backwards" when it travels over the S-drive.

You need to be aware that with the S-drive configuration, the head sprocket of the conveyor now needs to be built strong enough to resist TWICE the chain pull. This usually means a heavier shaft must be installed in the sprocket. The s-drive frame must also be built strong enough to resist the chain pull, as well as the conveyor assembly itself, which now may have chain pull forces applied to it between the head sprocket and wherever the S-drive is attached.

Conveyors can be driven by the tailshaft but usually they are level conveyors or close to level, since the chain slack is pushed to the top of the conveyor. Allowances must be made to accommodate the chain slack and it must be monitored closely because the slack cannot be allowed to become enough that the chain can wrap back around the tail sprocket and jam the conveyor.

One way of monitoring the operation of the chain is to arrange a limit switch on the chain return just behind the head end where a lever on the limit switch contacts the chain barrels. The switch is operated each time a chain barrel passes under it. This can be fed to a PLC or timer to act as a "chain breakage" or "chain stopped" sensor and can send a signal to your operators that the chain is not running. Of course, the switch does not have to be a physical limit switch. You could use a metallic proximity switch or a photoeye type switch to achieve the same result with non-contact technology.

Hope this helps. If you need a little more detail, please provide some clarification as to the actual problems.

Jon.

Previously no fire incidents took place which we can assume that everything as per design.Only recently,we connect a heat source pipe which may contain ember to the space below the driving motor.The idea of having this heat source is to heat up the fuel in order to reduce the moisture content of the fuel.Looking at the damaged/burnt motor supply cable,I assume it was caused by external heat not from overcurrent.By having the driving motor relocated ground floor I hope better monitoring and control in terms of fire prevention and ease of maintenance as well as cleanliness of the motor.It was located about 50 ft from ground floor.It is not a good ride.But still I have an option whereby not all of you object the idea.Thanks a lot friends.But my superior will decide.

In most modern conveyor applications the motor is at the "Tail" end, pulling the belt helps isolate problems, since you may notice slippage or streching faster than with the motor pushing the belt.

The problem you have may be associated to other factors as for example overloading the conveyor such that the motor can be damaged, or the product falls off causing overheating due to friction, etc.