You are not registered yet. Please click here to register!


 
 
plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
 
Try our online PLC Simulator- FREE.  Click here now to try it.

---------->>>>>Get FREE PLC Programming Tips

New Here? Please read this important info!!!


Go Back   PLCS.net - Interactive Q & A > PLCS.net - Interactive Q & A > LIVE PLC Questions And Answers

PLC training tools sale

Reply
 
Thread Tools Display Modes
Old November 19th, 2018, 12:19 PM   #16
Greg7683
Member
United States

Greg7683 is offline
 
Join Date: Jun 2018
Location: Plainfield IN
Posts: 334
Quote:
Originally Posted by widelto View Post
This images will clear everything for you:
https://www.google.com.co/search?q=t...w=1366&bih=626



All them pictures did was give me more questions what kinda math is that.
  Reply With Quote
Old December 10th, 2018, 03:37 PM   #17
Timeismoney08
Member
United States

Timeismoney08 is offline
 
Join Date: Jul 2012
Location: United States
Posts: 224
Quote:
Originally Posted by Tom Jenkins View Post
First LAW of Thermodynamics: Energy is not created or destroyed.

Power is energy per unit time.

Therefore the horsepower throughout your system is always the same, minus losses to friction, of course. Those losses turn to heat.

T = hp x 5252 rpm, with T in ft∙lb

So as the speed goes down T goes up in the same ratio. Always.


Understood, but what if the drive sprocket is much smaller than the drive roller that it's connected to? I know the RPM is the same, but when I'm calculating Torque, do I go by the drive sprocket or the drive roller?
  Reply With Quote
Old December 10th, 2018, 05:25 PM   #18
GaryS
Member
United States

GaryS is online now
 
GaryS's Avatar
 
Join Date: Aug 2003
Location: Lancaster Pa.
Posts: 843
you must first figure the torque required to move the load then figure what speed to want to move at.
Work back from their, sprocket size, gear reduction and so on.
I would try to size the motor to run close to 1800 rpm 4 pole motor as possible this will make the motor a standard motor then select the HP based on the calculation from the total reduction. I would add a little buffer and oversize the motor a little.
then use a good quality vfd sized to the motor.
  Reply With Quote
Old December 10th, 2018, 07:08 PM   #19
Tom Jenkins
Lifetime Supporting Member
United States

Tom Jenkins is offline
 
Tom Jenkins's Avatar
 
Join Date: Apr 2002
Location: Milwaukee, WI
Posts: 5,927
Quote:
Originally Posted by Timeismoney08 View Post
Understood, but what if the drive sprocket is much smaller than the drive roller that it's connected to? I know the RPM is the same, but when I'm calculating Torque, do I go by the drive sprocket or the drive roller?
Perhaps the attached will help. Torque on any one shaft, such as the headshaft, is unchanging.

Ignoring friction, power is unchanging throughout the system. (First Law)
Attached Files
File Type: pdf conveyor calcs.pdf (50.8 KB, 41 views)

Last edited by Tom Jenkins; December 10th, 2018 at 07:22 PM.
  Reply With Quote
Old January 10th, 2019, 04:42 PM   #20
Timeismoney08
Member
United States

Timeismoney08 is offline
 
Join Date: Jul 2012
Location: United States
Posts: 224
Specifying Motors - Over powered for application

I have a question regarding some calculations I'm doing...

I find that most of our motors are around 1/2HP, so for some applications we may install one and gear it down to fit our needs.

What I have a question regarding, is how much over on torque or speed is acceptable. I can run the numbers sometimes and get 100% speed match, but way over on torque, or 100% on torque and high on speed. I would average the two and go in the middle of each as long as the application will work with it.

Obviously this is a improper motor selected for the application, I'm just curious what is considered normal values.




Thank you!
  Reply With Quote
Old January 10th, 2019, 05:59 PM   #21
jraef
Member
United States

jraef is offline
 
jraef's Avatar
 
Join Date: May 2006
Location: Northern California
Posts: 1,613
Since you have already posted that as a new question (http://www.plctalk.net/qanda/showthread.php?t=119051) we should leave it there rather than continue the cross posting.
  Reply With Quote
Reply
Jump to Live PLC Question and Answer Forum

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
dc motors and drives > replace by ac ones Kataeb LIVE PLC Questions And Answers 9 October 29th, 2018 09:16 PM
Synchronize two motors with a Omron CP1L-EM and Omron Rotary Encoders Hartech LIVE PLC Questions And Answers 2 April 24th, 2018 01:48 PM
SErvo Vs AC motors haythame78 LIVE PLC Questions And Answers 8 March 10th, 2005 11:43 AM
120 volt speed control cciblazer LIVE PLC Questions And Answers 5 October 4th, 2003 03:45 PM
Motors! Motors! Motors! (Topic 3 of 3) akreel LIVE PLC Questions And Answers 16 February 11th, 2003 09:30 PM


All times are GMT -5. The time now is 11:42 PM.


.