Re: Conveyor Gear Box Efficiency Factor
Surely this information is best requested directly from gearbox manufacturers rather than "secondhand" on this forum??? ■
Firsthand Information
Second hand is here firsthand...or so I hope. I did look through all available supp. doc's & info's, for sure. As a rule I'm given an "approx." something, and a "we'll say more when you specify more ...". But what I'd like to have is some true numbers "as delivered". In my special case the importance lies in the percentage tenth' after 97,... or 96,...
There's this difference between the efficiency "by catalogue" and "as delivered" that makes my "problem"-gear reducer borderline on heat issues.
Roland ■
Re: Conveyor Gear Box Efficiency Factor
If your gearbox is that critical that you are worried about the difference between 97.5% and 98% use the next size up of gearbox.
When you buy your gearbox specify that it shall be tested for efficiency and the value supplied. ■
Re: Conveyor Gear Box Efficiency Factor
Right.
But this is future, and I'm in the past.
At a running system, and cannot make anybody buy offhand a next size gearbox just so.
In that application laughable 0.5 % of 340 kW, going into heating up of the oil, will not be matched by the heat dissipation ability of the gearbox. 1.7 kW are 22% of this dissipation value.
Thank you nevertheless for the interest.
Regards
Roland ■
Re: Conveyor Gear Box Efficiency Factor
Dear Roland,
Can you increase the heat dissipation capability of the gearbox with a self made extra cooler?
Mount an extra oil pump, which is driven by a small belt from one of the shafts.
The pump sucks the oil from the sump and returns the oil though a cooler back into the casing of the gearbox.
A thermostat before the cooler can keep the oil temperature constant if necessary.
Probably, you have to make 2 threaded holes for hose or pipe connections and some foundations.
That is all and the obvious temperature problem is solved.
Or is the problem more complicated?
Success
Teus ■
Teus
Re: Conveyor Gear Box Efficiency Factor
In my experience, large right angle helical bevel reducers always run on the warm side.
I was told it was because they pack more torque into a smaller housing for the same ratio.
In two cases, external coolers as described by Teus had to be retrofitted. ■
Re: Conveyor Gear Box Efficiency Factor
Dear Teus & J.D.,
thank you for your answers.
Yes, we did "invent" a selfmade cooler, using pressurized air from a nearby duct.
You know, I'd like so much to learn to recognize "borderliners" already at the planning stage and to avoid retrofitting after having given some "fun" to the purchasing dep. and management... They tend to not to understand such procedure.... Purchasing buys cheap without cooler, believing in the data from suppliers. Such issues (thermal) start to be perceived only some time after final delivery & acceptance. Mostly someone at installation just sets the temp alarm trigger 10 degs higher, and that's it until real trouble begins. I'm already glad if it is only the sealings that "melt" away, the leakage giving a hint. With mineral oil, one could end with damage to the tooth surfaces..
I'm looking for some tough enough number for use as a sensor / warning mark.
Best regards
Roland ■
Re: Conveyor Gear Box Efficiency Factor
Hello Roland,
I feel for you as the issue with catalog data is a systemic one in some areas. Take for instance ventilation fans for enclosures and buildings. I have to talk to plenty of disenchanted folks when they complain that some of our electric motor hp is quite a bit greater than commercially available ones online. That is because catalog data can sometimes be quite off from the application you are looking at.
By my book an estimate is still good engineering practice and your purchasing department had better take you serious when you add a 1% to your calculations.
With this small error in margin you may also want to try a PAO oil from Royal Purple. Their claim to fame is reducing BHP and heat in rotating equipment. They are not expensive as you may think. Synergy or Synfilm would be the product I think you need. Stick with PAO oil though.
http://www.royal-purple-industrial.c...i/indgear.html ■
Re: Conveyor Gear Box Efficiency Factor
Hallo Ralf Weiser,
thank you for this answer, yes, that's the point for the future: To simply ask "What if " there's 1% more loss than according to the efficiency figure given in offer, going into heat.
This time I'll have to bear with the fact: 97,76% is far too optimistic for this specific gearbox, the heat dissipation ability and / or heat compatibility had definitely to be upgraded.
I'm sticking to PAO as a rule, the more with these highend gear reducers. But sometimes my applications are quite far away from decent supply, so I must often use the "lowest common multiple" oil quality. Thank you also for the tip with RP.
Best Regards
Roland ■
Gear Box Efficiency
Normally based on the efficiency factor the ratio and size of the gear box will be changes, the most common bevel efficiency % for helical and worm normally considering the efficiency as 95 % and 70 % as a thumb rule , pls proceed with this type of so that in the power consumption of 350KW will be changed and over loaded
Regards
Kurra ■
Conveyor Gear Box Efficiency Factor
Dear Conveyor Drive Specialists,
I need to compare a 2 step bevel - helical gear reducer of nom. output power 350 kW, input RPM = 995 1/min, trans. ratio of 7, PAO-oil, axial cooling fan.
Could you give me please the FINAL (as delivered) overall gear reducer efficiency factor of similar reducers you know about?! It would be great to make it like this:
Manufactured in region... / EF = ...
for example:
manufactured in N.America / EF = 97,76%
Thank you very much in advance.
Best regards
Roland ■