I was asked recently if I knew why someone would use a "Power Band" (single outer cover, and I think power band is a Gates brand)) belt instead of multiple single "V"'s on a drive.
I haven't been around very many of the power bands, and the ones I have have been extremely noisy. It would seem to me they would be good for high shock loads (Be awfully hard to stretch them with torque), but I would also think you would have to have very good alignment and sheaves in very good shape so they wouldn't cut the outer band into ribbons, and make single belts out of the bunch.
What is your experience with them. Does anyone use them, and if so, what is the application and results.

Dave

This message has been edited. Last edited by: RRS_Dave,

Here's the gates info.
http://www.gates.com/brochure.cfm?brochure=3009&location_id=3781

Here are some comments from Rusty:

http://maintenanceforums.com/eve/forums/a/tpc/f/3751089011/m/8601004262/p/2

Thanks Epete,

I had searched and found Rustys comments, and I have the Gates design software.

I believe the single belts, aligned and tensioned properly are the best scenario for 90% of the comman drives we fool with (fans, pumps, etc.) but was interested in whether or not others had different experiance.

Thanks again for the interest and reply.

Dave

We use them on reciprocating pumps (mud pumps) on drilling rigs. The environment is noisy and the belts are "silenced" by two Detroit Diesel engines, 2 feet away from the mudpump.

You have to inspect the sheeves regularly, at least every 2 months, and don't use them in a dusty environment.
We had a similar setup on another rig, but with a chain drive, which was able to "silence" the engines.

Don't know if we were using Gates (other location), but power belt is I think the name for these multiple belts

quote:

good for high shock loads,

Seems like I saw exactly that comment in some vendor literature somewhere.

Yes Rusty,
I have too!.

The ones I know that are on high shock loads are one on a rock crusher, and two I am around on coal crushers (really rock crushers too).
They are high shock loads as you know, and they seem to handle it well with no slipping. But they sure do howl.

Dave

This message has been edited. Last edited by: RRS_Dave,

Dave,

I've worked around power bands for many years. Here are a few observations I've made:
1. Dirt, belt wear particles and other debris builds up between the belts and cannot escape due to the outer band.
2. Precise alignment must be maintained. A small amount of misalignment (especially angular) causes most of the load to be carried by just a few of the belts.
3. Due to the first 2 problems, the power bands tend to slip, causing squeeling noise. When most maintenance men hear that, the first thing they do is tighten the belts. That leads to overloading of the bearings, etc.
4. Sheave wear must be kept to a minimum.
5. Harder to install, and not usually done properly. Of course most single belts get pryed on too.

This is just my experience, but I've found more reasons to not use power bands that I have to use them.
As far as power bands being able to transmit more power, well, someone would have to prove that to me. In an ideal situation, all the belts on a multibelt drive system would be seated in the sheave with 100% contact between the sides of the v-belt and the sheave v-groove. Weather its a power band or single v-belts, the contact surface area is the same. So how can the power band transmit more HP than the singles?

Don

Don,

I agree and alsoquestion the cliam that they transit more torque.

In my experience, they are often used in areas where excessive flop is seen. That is usually a function of uneven tension due to misalignment and sheave wear but a special belt is easier than actual corrections.

It is easier until the mechanic starts trying to "roll" a banded belt onto the sheaves.

As I see it, the bands can only serve to keep the belts from slipping at different rates, thus increasing wear in both the sheave and belt.

quote:

The correct way to install this system is to loosen the drive mounting mechanism, install the belts onto both drive components, then align & tighten drive system as necessary.

I vision 1 or 2 mechanics, with a big pipewrench and a prybar or big screwdriver (to roll on the belts) and behind them the maintenance boss and the operations boss, to speed up things because of the downtime.
There are still place in the world where alignment is done with the straight edge of a sawblade

Steven,

You use the straight edge?

Danny

Gary,

Your comments about howling during operation and positive traction makes me wonder if we are all talking about the same thing.

My understanding is that we are talking about banded v-belts. I have never noticed them being any louder than regular v-belts. What I have noticed being much louder is the cogged tooth, positive drive belts (T. B. Woods HTD drives were the original with copies after the patent ran out in the early 80's).

You are indeed fortunate to work with such a group of pros and without the maintenance and operations bosses that Steven mentioned. I thought they were required in every plant.

Danny

Danny,

You are correct and I am wrong! I will delete my post. I got my drive belts mixed-up.

That's what I get for composing a reply before my morning coffee! Also, I got shut-out fishing too!!!

Gary Forsythe

Gary,

Maybe you should go back to bed and start fresh tomorrow.

Danny

The power band is good on slow start, step start, DC or when it is not an instant-on load. The power band operates ~96% eff and is good at its original setting while the V needs re-adjusting after two weeks and more maintenance with less life and only ~88% eff

I hope I'm coffeed up!!!!!! and on the right track. But at 30% additional cost they are the cheapest in the long run if your application will allow them.

Danny,

Good advice! I get up at 2:45AM & get to work by 3:30-4:00AM so I can get off early (around 11:30AM-12:01PM...then I go fishing.

We use the power bands on centrifuges and as you indicate, they do not 'howl' and the environment is not dusty. It is a high torque application requirement and the belts normally last about 8 months between change-out, based upon good sheave alignment.

About the only thing I got right is my comment regarding Unnico Services. The fellows I work with are very good professionals & maintenance craftsmen.

Sorry about the mix-up.

Gary Forsythe

Glad to see you chime in Two Dogs.
Lets me know you're still kickin

Dave

quote:

You use the straight edge? Wink

Danny I didn't grab it, guess because english is not my native language

But friday night I was chatting with a friend (engineer) from another company about the transition from dial indicator to laser alignment.

His answer: If I am lucky, somebody has a broken sawblade in his toolbox. We both had a good laugh about the expression

In my vision I forgot to mention the rest of the club. The typical setup: too many chiefs, no indians

Steven,

It was sarcasm meant to imply that some places are using the tooth edge of the saw blade and havn't even caught up with the ones who are using the straight edge.

You need not apologize for your English, it is quite good and I wouldn't have noticed that it is not your first language if you hadn't pointed it out. I'm certain that your English is much better than my ability to communicate in your native language, no matter what it is.

It's Dutch, isn't it Steven?

I agree, your English is quite good. This comes from the Southeastern US(just a few miles down the road from Ralph) where we have achieved greatness in the art of reliability, but we have not yet mastered English.

Yes Richard it is dutch, but technical dutch is worse than bad english, I can't even find my way around Micro$oft word if it is translated to dutch !