Selecting a DC Motor 4

[Barbo88]

Hi everyone,

I have a conveyor belt system which needs to carry heavy stuff. I have done all the necessary calculations and i'm looking for a DC Motor (I can't use an AC Motor). Can someone help me please to find the right motor for my system ?

Parameters required: - Speed required form the motor (MIN) - 5.5 RPM
- Torque required from the motor (MIN)- 35 Nm
- Power of the motor should be - 20 W

I would be very grateful if you can help me to find a proper DC Motor.

Best Regards
Barbo

 

[waross]

Consider a gear box. 5.5 RPM is pretty slow for best economy of size.
Will 20 W overcome friction??

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Barbo88]

Yes, I already calculated the friction loss.

Do you know any good sites from where i can find a good one ? and which motor and gearbox do you suggest in your opinion ?

Regards
Barbo

 

[waross]

Here are some motors with built in gear trains.

http://transmotec.com/dc-motors/planetary-gear/PD22-Series.aspx

http://download.transmotec.com/eng/dc-motors/planetary-gear/Transmotec-DC-Motors-PD-0.6W-35W-eng.pdf

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[Barbo88]

the torque in these brochures has a unit of mNm. What does it stand for exactly ? milli Newton Meter ??

 

[ozmosis]

Try Parvalux

http://www.parvalux.com/index.php?id=66

 

[Skogsgurra]

"a conveyor belt system which needs to carry heavy stuff"

I'm afraid you need to check your numbers. A conveyor belt that carries "hevy stuff" doesn't sound like a 20 W animal. More like 20 kW - or at least 2 kW. Why can't you use AC?

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[mikekilroy]

agree: why can't you use ac motor?

35nm (28#-ft) @ 5.5rpm is indeed only .02hp or 20 watts....

- how long does it have to last?
- run 24/7?
- need to be sealed? IP67? IP69? washdown duty?
- how smooth?
- +/-0.5rpm ok?
- how do you turn it on and off and adjust speed?
- do you need a controller for it also?

not enough info to pick a $ 120.00 unit from grangers catalog with worm gearbox (dayton, ohio, leeson, etc) or a $ 2500.00 one with precision planetary gearhead and tach feedback or encoder for position feedback.

 

[itsmoked]

Ditto !

And

http://www.robotmarketplace.com/products/motors_main.html

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

Actually, "35nm (28#-ft) @ 5.5rpm is indeed only .02hp or 20 watts...." is what I question.

First, 35 nm is a very small distance, not a torque, but if we assume 35 Nm instead, the 5.5 RPM results in 35*5.5*6.3/60=20 W - as said.

But that isn't a conveyor for "heavy loads" and that is where I think that the input data may need to be checked again. It may also be that this is a medicine or similar application and then, a heavy load can be a couple of kilograms - not tons.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[mikekilroy]

thanks for the NM correction. sorry for confusing folks with my non caps. i never imagined anyone could misinterpret Nm vs nm in context.

i could say i will try to do better with my capitalization in the future, but, alas, i doubt it will happen. i seldom use caps any more. i often refer to u in shorthand (vs you in case this too is misunderstood), and suggest we r helping each other with engineering concepts here anyway, and likely will continue using my ham radio morse code shorthand.

but one thing i try to use well is the Oxford Comma. even educated folks can misinterpret statements without proper punctuation. i surely would not want either of the following misinterpretations due to my missing or misuse of the serial Oxford comma:

we invited the strippers, JKC, and Stalin.
-or-
we invited the strippers JKC and Stalin.

I helped my uncle, Jack, off a horse.
-or-
I helped my uncle Jack off a horse.

sorry again for my typing methods folks!

ac8v

 

[Barbo88]

Hi guys,

First of all thanks for your information, i really appreciate. So, to be honest i know that these parameters doesnt make sense enough for the application.

So to be more clear, I was given this problem and i have to find a proper motor for this system (I was asked to use only a DC Motor so I can't use an AC Motor). The system consists of a 20m conveyor belt which is going to be used to carry 1200kg of coal per hour (Maximum) and 600kg of coal per hour (Minimum) so for sure i need to vary the speed. I just did my calculations and found out the required speed from the motor and the required torque to carry that amount of weight per hour. I calculated this on the maximum amount, which is 1200kg per hour. So, actually i'm looking for a DC motor and a gearbox to be able to satisfy the required job.

Appreciate if you can guide me to find the right motor.

Best Regards
Barbo

 

[Skogsgurra]

So, you need a lot more than 20 W! A coal conveyor belt starts at at least 2 kW. 20 W is ridiculous.

Does the conveyor run horizontally all the way? Or is there a height difference between the ends? That height difference is also important. And what about roller friction? You cannot cover that alone with a mere 20 W.

And, that guy that told you to use a DC motor - doesn't he know that AC motors can be speed controlled these days?

I refuse to "help" in a situation where a blind leads a blind. Nothing good comes out of it.


And, mikekilroy, we are engineers here. And there are conventions on how to use prefixes and dimensions. That is how we avoid getting into trouble. Do use the correct dimensions and prefixes, please. If you think that you shall introduce some "personal style" in engineering - please change your mind.


Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[Barbo88]

Hi Skogsgurra,

I know it's stupid and doesn't make sense this given problem. However, there is no inclination so the conveyor is completely horizontal while the friction coefficient is about 6%.

Best regards
Barbo

 

[waross]

Have you got your units confused??
20 W is 1/37 HP.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[mikekilroy]

Skogsgurra saZ: If you think that you shall introduce some "personal style" in engineering - please change your mind.

Nice.

one day I will die and you can continue on being the super wizard. why not refrain from such nonsensories until then my friend? it is quite obvious you do not like me and somehow consider me a an adversary to you. so be it. perhaps in the meantime you can control your temper? live on my friend.

 

[waross]

For the record, Skoggs is not the only one who feels that lower case and IM abbreviations are unprofessional.
Oh, by the way, with over 800 votes received, Skoggs does not have to appoint himself as super wizard. Others have already.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

Mike,

Rein it in a bit.

Skogs didn't decide on the abbreviated forms of measurement units. ANSI and SI did. The rest of us manage to follow convention, because if we don't then our ability to communicate falls apart. Using your thought process you might as well swap a 2 with a 6 or a 7 with a 3 whenever you feel like it. After all, you know what you mean and, hey, it a free world. Who cares?

As for txt-spk, if that is your chosen way to communicate then I guess there are places where it is the norm. Here isn't one of them. Many of the members do not have English as their native language - the Americans for start - and using txt-spk makes life unneccesarily difficult for them.

FWIW I hope you do stick around, but without the arrogant attitude shown in the last couple of posts.

 

[electricpete]

Anyone who thought nm meant nanometers in the present context?

Show of hands....

Seeing none... obviously… we all realize that the reason we are having this discussion was a stray comment that had nothing to do with the current post.

Mike was attempting to respond constructively to original poster. He did not ask for people to grade his grammar / case nor to debate his polite response to the unsolicted, unecessary, and irrelevant criticism.

Hang in there Mike.


=====================================
(2B)+(2B)' ?

 

[Barbo88]

So guys, i just found an appropriate DC Motor for my task as regards the parameters that i calculated. This task is required to transfer between 600kg and 1200kg of coal per hour. I just did my calculations on the maximum amount (1200kg) so theoretically i found the required speed (RPM) of the motor which is about 6RPM, and the initial Torque (with the load on the conveyor belt) which is about 35Nm. However, i was thinking that since it is required to transfer between 600kg and 1200kg of coal per hour i should include a speed controller so the operator can vary the speed. What i was thinking about was to use a PWM pulse with modulation to vary the speed by changing the frequency however, my question is, if i change the speed with a PWM will i change also the Torque ?

This is the motor which i found suitable for my system.

http://www.parvalux.com/images/stories/configurator/datasheets/PM11MWS.pdf

Appreciate if you can guide me through your experience guys.

Regards
Barbo