How to know whether to Replace motor brushes or not. (Video 93)

[@monicagranucci5081]

Thank you so, so much for this video!! I was just wondering how to check the health of my motor, you've given me the confidence to open it up and to know at least one thing to look for.

[@randyyoursewingmachineman9954]

You’re welcome and thanks for watching. 😎👍🏼

[@tiogoala7654]

Thanks for the information Randy.

[@randyyoursewingmachineman9954]

@@tiogoala7654 you’re welcome and thanks for watching. 😎👍

[@ronalddevine9587]

Wow, 2 videos in one night. I may not be able to sleep!!! Randy, I've heard that the replacement brushes aren't as durable as the originals. Any thoughts? Yeah, I've replaced in my 201-2, and 66-16. Fun City. Stay well my friend 🙏

[@randyyoursewingmachineman9954]

It’s like many replacement parts, made more for profit than longevity I guess.

[@annesummers09]

My motor (kenmore motor E-6354) purrs like a kitten when it is off the machine, but makes a grinding kind of noise when installed. The sewing machine itself also purrs when the hand wheel is turned without the motor. But if I put the motor on, it runs but makes awful noise. I took motor apart and it looks good inside. Brushes are half way down. Motor itself is in very good condition, not dusty, dirty or junked up. I oiled the bearings, too. Why does it sound so bad? Thanks.

[@randyyoursewingmachineman9954]

I wish I was there to help figure it out. That’s a puzzler for sure. Make sure that the fins on the armature fan aren’t rubbing against the motor housing. Could be that.

[@annesummers09]

@@randyyoursewingmachineman9954 Thanks, I'll check it out.

[@krystleroy3068]

I have this issue with the elna serger motor! It smell weird like metal and gets hot quick! I know I need to replace brushes and it’s probably dirty as well if I can’t I will replace the motor

[@randyyoursewingmachineman9954]

Make sure the belt isn’t too tight and don’t oil the motor excessively. Blow it out with canned air.

[@r.duroucher225]

I have a quick question for you Randy, I have a motor that buzzes when started at low speed. If I press down on the foot pedal all the way, the motor starts, but if I want to start off slowly, I generally get buzzing and I have to turn the hand wheel or press down more on the foot pedal. Any ideas of what I can do to optimize the motor or somehow fix this? I cleaned the commutator and replaced the brushes, but it still does that. Any help would be appreciated.

[@randyyoursewingmachineman9954]

That sounds like a motor that has had a lot of use and the motor bearings are out of spec. You’ve probably done the logical stuff, like a drop of oil on the bearings and making sure that the belt isn’t too tight. Sometimes I can change the brush springs and that reduces the pressure of the brushes as they contact the armature. I would also check for a “hot spot” on the armature and smooth it down, in order to get it more consistent contact with the brushes. Take the belt off and cycle the motor wide open fast and let off to zero speed. Like pressing on the foot control all the way and then let off repeatedly. Watch the pulley end of the armature shaft and notice whether or not it torques back and forth, or just runs straight and true. If you see the back and forth movement, the motor has worn bearings. These electric motors are usually super robust, especially the older ones. But they do wear out. It may be time for that motor to transition to sewing machine motor heaven. ( or wherever they go) Good luck.

[@r.duroucher225]

@@randyyoursewingmachineman9954 Thanks very much for your reply Randy. Yes, I've done all the logical stuff, I've not looked at the springs on the brushes. I didn't think of that. It may be that the brushes are pushing too hard I just changed them and the new springs may be too tight. I didn't now about the movement on the shaft issue. The shaft does torque back and forth, and the motor may simply have too much wear to ever work like new. It probably has had a great deal of use. The motor is on a 1948 Singer 15-90 that I was sitting out in the street and then sat in a damp basement for about 20 years. It was entirely seized, jammed up and rusted. I took the project on as a new COVID hobby and after lots of very happy time spent, a quart of kerosene, a can of WD-40, a bottle of rust remover, a half bottle of sewing machine oil, rewiring, refurbishing the carbon pile foot pedal and some dismantling and refurbishing of rusted and seized parts, it's now rescued from sewing machine heaven. The machine works beautifully, except for the slow-to-start buzzing motor. The motor works fine once it gets started though. I may have to decide to live with it until it completely gives up the ghost. Thanks again for sharing your expertise!

[@randyyoursewingmachineman9954]

@@r.duroucher225 you’re welcome. With that history, that motor and its new brushes may have to have a “run in” period where the brushes get in a new groove. It may get better as time and use dictate. Have fun.

[@r.duroucher225]

@@randyyoursewingmachineman9954 I think I've got it solved. First, I took your advice, a drop of oil in the bearings. Second, cleaned the commutator one more time, there was some build up of carbon that resulted from the brushes running in. Third , and this made all the difference, I adjusted the travel in the foot pedal. It's a carbon pile foot pedal and the adjustment screw was too loose. By tightening it up I was able to get the foot pedal to provide far greater accuracy in terms of the amount of power delivered to the motor. I wouldn't have thought to look at the foot pedal but for your comment about the brushes needing to run in which got me thinking about cleaning the "run in" carbon dust off the commutator which got me thinking about how power was being delivered to the motor. As one pressed the pedal, it was essentially delivering far too low an amount of electricity to turn the motor, which then buzzed but didn't turn, and then it jumped to a high power with little control in between. Is the motor perfect, nope. It is more than a little bit worn. But does it work really well, Oh yes, sure does. Lots of control, lots of power. So Randy, thanks for taking the time to share your expertise! I would still be puzzling and puzzling what to do if you hadn't shared your thoughts.

[@randyyoursewingmachineman9954]

@@r.duroucher225 good job in solving the problem. Max power equals max performance. Logical.

[@judinesewell9676]

😭😭😭 so mine is that 3rd one, the brush is irreplaceable???

[@randyyoursewingmachineman9954]

If you don’t see the screw caps, the motor brushes aren’t easily replaced. It’s really a job for a skilled motor rebuilder. For a motor that inexpensive, I wouldn’t bother with all the time and trouble. Always make sure that the problem is the motor and not elsewhere. I test them by applying direct current to the two leads with the motor belt removed. If it runs at a high speed, the motor is probably good.