Direct Drive or Belt Driven Fan

direct drive is better than belt driven because belt driven is mostly for small fan and small torque. its depend on the size of the imepller and the rpm of the fan.

r u working in Kualiti Alam? INC1?

One advantage to using a belt drive is that the process is separated from the drive motor. In some cases this is a temp and environmental issue.

This design also allows a tech to grease the motor bearings while the machine is in service increasing the uptime of the machine.

Direct drive makes for a nice and clean installation, but if 24/7 service is needed a cogged belt drive is hard to beat.

There will be about 10% losses in the belt driven fans. Hence direct drive is recommended to the extent possible. Direct drive fans not only reduce the power consumption of fans but also the spare and replacement cost of belts.

If you donot have any problem right now with the present system, the present system is most effective, since the Total ownership cost of equipment will increase heavily if you shift to belt driven system.

Direct drive is simplest when its running but harder to work on when it fails. Belts require "touching" more often to keep tension and alignment within standards. So my suggestion is if your budget allows purchase a spare complete direct drive unit and you should have the lowest down time for a reasonable price.if budget is tight buy spare belts, belt dressing, pillow block bearings, a good straight edge, belt tensioning tool and of course an amp probe. Check the direct drive unit monthly, keep it lubed and belt set properly and it should last a long time.

I assume this is a fairly small fan.

tq guest, CrossFire, danuquri and miketheboilerguy for your reply

I will take all the answers into my consideration later on.

here is my conclusion:

-smaller fan performed better with belt drive rather than direct drive.

-direct drive fan give more impact on the CAPEX while belt drive give more impact on OPEX.

-direct drive is more reliable in rugged condition (dirty dusty air and 24/7 running) and high RPM but gives more problems when it fails.

-belt drive perform better in clean air condition and low RPM but need more maintenance (belt tightening and aligning).

i hope i got it right...if you see any error with my understanding, please correct me. TQ

-AFA-

if u feel free kindly discuss with us Engineering Department..tq

tq BELLray..i will definitely love to discuss with you on this matter...

-AFA-

There are advantages to the belt drive system that have not been mentioned. If your incineration plant is moving anything but clean air, eventually your fan blade will build up debris on it or start to corrode if fabricated from aluminum which is common. This will cause a unbalanced condition. If the fan blade spins on it's own bearings the wear will be easier to repair than if the bearings are part of the motor. Additionally the choice of motors will we greater if it is separate from the fan blade. Good luck.

I agree with Bob C here.

We have a belt driven fan for the exhaust system in our paint booth.

We had a fire in the stack from someone smoking around the filters. I don't know how that happened but that's what the fire department report stated.

The paint build up along with the dust accumulation in the stack became a fire hazard and caught fire. I think it was the fan blades rubbing against the waste build up creating friction.

I was not at work that day, but the guys that were, discharged dry chemical fire extinguishers up there and sprayed water from a hose up there and none of them had sense enough to shut off the power to the fans. So the fan just sucked all that right on through without doing a bit of good.

Had it been a direct drive fan we stood the chance of getting water in the electrical motor, that would have created additional problems.

After you establish your air volume and pressure needs you will talk to fan manufactures. I have purchased many industrial blowers and the drive method is often established by the use. I am just talking in generalities but direct drive fans obviously turn motor speed and motor speed (often 1750 RPM) is often faster than you want a fan to turn. For larger non high pressure fans this is usually not the first choice. Higher blade tip speed fans wear faster than lower tip speed fans, especially if you have any particle loading.

My best advice is contact manufacturers after you have established the critical attributes, then make sure you understand their recommendation so you can verify it is technically sound.

KISS use Direct drive. No belts to wear out, no pulleys to align, no bearings on a fan shaft loaded by belt tension to wear out, no lateral load on motor bearings. Less maintenance. More compact.

You would prefer to have thrust loads on the motor bearings?

With the newer power cog belts, the side loading on fan shaft and motor bearings is very low, no belt slippage is also a plus.

I have worked around 150Hp air blowers that are belt driven with a cogged belt. The unit ran 24/7 with no down time for over 3 year because of failure. We where able to maintain the shaft bearings with remote grease fittings and flush the motor bearing while the unit was running. I have not seen a belt related shut down with the cogged belts when properly maintained.

I have also worked around smaller direct drive fans and cage blower. both types ran 24/7 but maintenance in a direct drive is more difficult while online.

If the fan is going to be used to create suction at an incineration plant, I would guess the process would be very warm. Not the ideal application for electric motors, wiring adn monitoring equipment like Vib switches.

Hi, afasy1968!

Two points in favour of direct drive: more parts = more parts to break down; and in the incineration plant, more stress on more parts = more parts to break down.

I don't count the drive shaft as a separate part because regardless of whether the fan is direct drive or belt-driven, the impeller still needs an axis, and the shaft on yours can't be replaced with something else. I am also assuming (not a huge leap, thankfully) that the motive force for the impeller is (hopefully) outside the ducting.

Mark

I think belt driven systems are considered one from the first trials for power transmission. And as danuguri said at post #3, there will be about 10% losses in the belt driven fans, and I think this figure will be increased in case of belt sliding. I prefer and recommend using of the direct drive fans.