Fan AC Motor adaptive use - problem

Click For Summary

Discussion Overview

The discussion revolves around the adaptation of a 60W A/C fan motor to operate two spindles at different RPMs, addressing issues related to excessive heating and motor failures during continuous use. Participants explore potential solutions and specifications for selecting an appropriate motor for the load involved in winding threads.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant suggests rewinding the failed motors with a higher gauge copper wire, questioning if this could mitigate overheating issues.
  • Another participant counters that changing the wire size would likely increase the motor's operating temperature, proposing instead to use higher temperature insulation or to improve cooling by blowing air over the motor.
  • A third participant discusses the characteristics of AC motors in the 60W range, noting that they are often shaded pole motors which can run hot due to their design. They mention the potential benefits of using a permanent capacitor start-run motor instead.
  • Concerns are raised about the feasibility of rewinding small motors due to safety standards and cost implications, with a suggestion to consider well-defined induction motors instead.
  • One participant provides specific details about the motor's temperature rise and operational specifications, raising a question about whether the motor is faulty after observing a failure when stopping the shaft under load.

Areas of Agreement / Disagreement

Participants express differing opinions on the effectiveness of rewinding motors and the implications of changing wire gauge. There is no consensus on the best approach to address the overheating issue or on the reliability of the current motor setup.

Contextual Notes

Participants discuss the importance of understanding load specifications and the potential risks associated with using motors not designed for the intended application. There are mentions of safety standards that may be violated by rewinding motors, as well as concerns about bearing wear due to improper loading.

Who May Find This Useful

This discussion may be useful for individuals involved in motor applications, particularly those working with A/C fan motors, spindle operations, or those seeking to understand motor specifications and performance issues in practical settings.

acmotor
Messages
2
Reaction score
0
We have adapted a 60W A/C Fan Motor, 1500 RPM to run two spindles one at 6000 RPM and the other at 500 RPM using pulley & belt. On continuous use the motor heats up excessively and a few fail.

Load is winding of threads from a Cone to a bobbin.

I need a few suggestion

i) Can rewinding the failed motors with a higher gauge copper wire solve the problem.

ii) How do you determine the load and create specification so that I can buy an appropriate motor capable of handling the load.
 
Engineering news on Phys.org
If the motor is properly designed and operating on the correct voltage, changing the wire size will make the motor run hotter.

Rewind the motor using a higher temperature insulation may be an option.

Blowing air over the present motor may be a solution.

Get motor with twice the horse power?
 
AC electric motors on the 60 W range are in an awkward wattage range which is too low for induction motors (usually 1/6 HP-125W) and up. The really low (and cheap) HP motors are called shaded pole, because a resistive copper strap surrounds part of the pole. These get very hot due to the resistive copper strap (needed to produce a starting torque). There are some permanent capacitor start-run ac motors that use capacitors rather than resistance to shift the ac phase. What are details of your motor?

LOWER gauge wire has LESS resistance. Fractional HP split phase motors use wire resistance to produce a phase shift in the starting coil, so changing wire gauge will change starting torque.

Start your search in the Grainger catalog:
http://www.grainger.com/Grainger/motors/ecatalog/N-bii?op=search

Bob S
 
Last edited by a moderator:
Rewinding small motors is probably a bad idea because you'll violate the UL/CSA/VDE underwriting. Along with that, you'll have the cost issues.

When you're uncertain of the load, it's good to try an induction motor that's well defined. Run it at it's rated voltage, and check the shaft RPM and current draw.

Be careful of shaft loading. If you've got pulleys, but your motor is designed a simple fan, then you're likely to wear out the bearing prematurely. Ball bearings hold up to these radial loads better than the more common sleeve bearing.

You might go through this site for motors:

http://www.emersonmotors.com/products/ecatalog.htm
 
Last edited by a moderator:
Further specification on the motor mentioned Temperature Rise < 75 K [I am unable to figure the temperature rating]

Also it uses a 2muF 450V capacitor

Onload Spec
A = 0.3 A
P = 60 W
RPM = 1350

230 V, 50 Hz Capacitor Motor

I tried running the motor with no load for 20 minutes and noted temperature 52 C [126 F]. Then used my hand to stop the shaft for a second or two and the motor failed. Is the motor faulty?

Thanks
 

Attachments

  • Image0262.jpg
    Image0262.jpg
    18.5 KB · Views: 499

Similar threads

  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 7 ·
Replies
7
Views
4K
Replies
1
Views
3K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 14 ·
Replies
14
Views
49K
  • · Replies 55 ·
2
Replies
55
Views
9K
  • · Replies 20 ·
Replies
20
Views
6K
  • · Replies 16 ·
Replies
16
Views
13K