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sizing a AC (drive) motor for a system that requires 3 separate outputs

sizing a AC (drive) motor for a system that requires 3 separate outputs

sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi, I was hoping someone could help me calculate the size of a drive to run the following,

1. a pinch roller pulling a wire total force 50n, roller radius is 28.559, 100 rpm

2. a lobe (cam roller bearing) swung off a shaft pushing a piston arrangement down, needing 100kg of force perpendicular to the shaft, shaft being 80mm diameter - with the lobe protruding 2.5 mm (42.5mm radius), the piston has a roller contact the lobe. the shaft is turning at 1200 rpm.

3. a cam spinning at 1200 rpm - throwing a pendulum anti & clockwise 2.5 degrees, ark length only 7.5mm - so 1200 is really 600 cycle clockwise and 600 cycles anticlockwise. the pendulums mass is about 8kgs, with a 120mm moment arm, some weight is around the bearing housing and some situate around the cam mouth which is on the same swing radius of approx 100 mm. the cam is set into a birds mouth arrangement.

I calculated that I would require 4 to 5 kilowatts approximately. i would use double sided timing belts to drive all axis from one motor with a servo drive

your help would stop many sleepless hours. if you can make sense of my question.

many thank s Michael

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi,

Sounds like reciprocating masses so acc's en dec's hence fluctuating moments and power.
Please post a skeleton sketch where masses and work distances be seen.
So a moment curve per motorshaft rev can be figured out.

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi jlnsol,

I am struggling to find a way to post the sketch, the area below for an attachement will not work for me.

Michael

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi j,

for some reason I cannot get this to open my browser - must need to change something,

still trying

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)


well there you go - went thru and tried 4 only firefox has worked

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Michael,

Let's start with the pinch roller set. Is the 50N the pull force in the wire?

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs



The force to drive the pinch set can be much higher because of bearing friction. See figures in this example calc.

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi jinsol,

I would like to thank you for the help - I would be lost without it.

Using a hand held scale it took about 5kg to pull it.

I will take the time to write up a spec and re-post the drawing, might make thing easier having all info.

regards and thanks

Michael

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Micheal,

I can't read the text. Can you please upload the picture as an attachment instead of clipping into the post?

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Thanks, it is clear now. I will look into it and get back to you.

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
good day j.many thanks, its is very complex and so different to the norm, I am thinking, hoping to use double sided timing belts to tie the 3 drives together, any thougts from your end.

regards
Michael

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Michael,

Just a few points to clarify if I understood this correctly:
A. pendulum arc travel distance at 95,5 mm radius is equal to the eccentric cam offset is equal to 7,5 mm
B. 7,5 mm arc at radius 95,5 mm is a pendulum swivel angle of 4,5 degrees
C. cam is rotating 1200 rpm, so there are 1200 clockwise and 1200 ccw swivel movements of the pendulum per minute
D. 1 cam rotation takes 0.05 seconds, so a clockwise pendulum movement of 4,5 degrees takes 0.025 secs and the ccw movement of 4.5 degrees takes another 0.025 sec being total 0.05 secs

Are you OK with these observations sofar?

Regards,
J

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi J,

thanks for showing some interest in this contraption.

A. correct
B. correct
C. yes correct
D. again correct

All is observed correctly j.

I will have to check my notes, I think I have stated something wrong on the sketch - that you have made me aware of, the speed of the pinch rollers is wrong - maybe ??, I will look at it !!!!

regards

Michael

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi j,

pinch roll speed is ok at 100 rpm.

regards

Mike

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Mike,

In the attached pdf you can see what I found to be the torque and power curves to drive the eccenter shaft for generating the pendulum swivel motion only.

Is this in your area of expectation?

This is another part of the total torque and power sum you're after.
J

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
HI jinsol,

I will apologise for not responding earlier though your post did not reach me. Not sure why it has not hit my outlook -email.

what I have seen from the tables you have created is very correct.

thanks for your help and patience,

best regards Mike,

PS; I was wondering what was happening, hope all is good and will say thanks again

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Mike,

No problem! Understood.

Although I decided to quit posting to be honest...because of no reply at all.

Best regards,J

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
sorry to here that you have pulled the pin on this, your help was the only source I had to see this project move forward, if you ever change your mind I would be very appreciative of the assistance, as I have no skills in this field.

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Mike,
Your project requires skills and time. Lack of time and no reply were the cause to quit. I see that mail wasn't functioning... How much time do you have to solve this drive determination?

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi J,

The project has come from the need to simplify a process, if this prototype works then we have accomplished a great feat. I have the time I am able to draw and source information, though I lack the skills which you have to add the correct and much needed engineering.

As for the no reply, - as far as the notification of your post - nothing came thru to my email account re your last post - I took it that you were to busy and I really didn't want to push the subject onto someone helping out. I didn't check the site as I was fully reliant on the post coming to me via email, this will not happen again, learnt that lesson.

This project is important to me, I have no else help at this point, I was so very happy for you to show so much interest and so very disappointed to see you lose faith in me.

Very best regards

Mike

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Mike,

I am busy too, but I will continue to help you out! Hopefully post new stuff tomorrow!
Regards,
J

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi J,

I appreciate your help, please do not put this before anything important. Time will see this work out.

again thanks

Mike

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

(OP)
Hi J,

I have been reading and studying what you have done to date, it is hard for me to understand the engineering, whilst I have a natural feel with building - I do wish I had your skills, so far it is all looking really good.

I was at the stage of just throwing a 7 or 8 kilowatt 8 pole motor and VSD a few timing belts and pulleys and keeping my fingers crossed.

again thanks

Mike

BTW - what country are you in - I am in Australia - Sydney Australia

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Mike,

Good to hear that you studied what I wrote.

RE: sizing a AC (drive) motor for a system that requires 3 separate outputs

Hi Mike,

Finally I arrive at a 4,9 kW 1200 rpm motor. It appears that the cutting force 100 kgf of the rocker driven by the lobe shaft is by far the main power consumer. I added a 1,5 operation factor (for losses by friction etcetera).
See attached zip file.

Regs
J

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