Rotor gets tight when the front is put on. Emerson 1510

[Russ Huber]

Tim, all the dielectric grease concern aside, when you engage power on your video, you can hear the start/run windings energize. How snug is your rotor as far as end play? Is there much if any end play (rotor play back and forth) on the bearing shaft. 

[Tim Babcock]

1 hour ago, Lane Shirey said:

Yes, if you want to use something, there is contact enhancing grease used on radio tuners. But not dielectric grease. 
 

I don't agree. I was an Electrician for several years. We used dielectric grease on many connections. I use it on all my fan switches. Never had any issue. Its not conductive but its not an insulator either.  I checked to make sure I was not misremembering it. Got a conformation from one of the Electrical Engineers I know. "Dielectric grease is neither conductive or insulative. It is specifically formulated to lubricate and protect electrical connections from corrosion that will ultimately cause higher contact resistance."

[Chris Campbell]

33 minutes ago, Tim Babcock said:

I don't agree. I was an Electrician for several years. We used dielectric grease on many connections. I use it on all my fan switches. Never had any issue. Its not conductive but its not an insulator either.  I checked to make sure I was not misremembering it. Got a conformation from one of the Electrical Engineers I know. "Dielectric grease is neither conductive or insulative. It is specifically formulated to lubricate and protect electrical connections from corrosion that will ultimately cause higher contact resistance."

There is no substantial advantage of adding grease to the centrifugal contacts. 

[Russ Huber]

The grease itself is non-conductive. But the thin film of the grease on the spring pressured centrifugal contacts has a low probability of fowling the start winding circuit.  FWIW...it is not needed on the Emerson centrifugal switch mechanism and will more than like act like a dust and lint magnetic over time. 

Now, back to what is hanging up that rotor? 

 

Despite the fact it has "electric" right there in the name, it's a fairly common misconception that dielectric grease is capable of conducting electricity. In actual fact, dielectric grease is an insulator and doesn't conduct electricity.

 

[Tim Babcock]

38 minutes ago, Russ Huber said:

The grease itself is non-conductive. But the thin film of the grease on the spring pressured centrifugal contacts has a low probability of fowling the start winding circuit.  FWIW...it is not needed on the Emerson centrifugal switch mechanism and will more than like act like a dust and lint magnetic over time. 

Now, back to what is hanging up that rotor? 

 

Despite the fact it has "electric" right there in the name, it's a fairly common misconception that dielectric grease is capable of conducting electricity. In actual fact, dielectric grease is an insulator and doesn't conduct electricity.

 

I think you are conflating two different things. The Dielectric grease is not a conductor but it keeps corrosion form happening on contact points. I have used it for years on all my auto, plow, trailer ect contacts. Keeps water and corrosion from happening. If your Hypothesis was correct, non of my plow or trailer contacts would work. It is on my Truck and trailer light contacts now and works just fine. This video shows how Dielectric grease works.

 

[Russ Huber]

9 minutes ago, Tim Babcock said:

I think you are conflating two different things. The Dielectric grease is not a conductor but it keeps corrosion form happening on contact points. I have used it for years on all my auto, plow, trailer ect contacts. Keeps water and corrosion from happening. If your Hypothesis was correct, non of my plow or trailer contacts would work. It is on my Truck and trailer light contacts now and works just fine. This video shows how Dielectric grease works.

 

Cool. I am not challenging you. As a matter of fact, I pointed out if you read my last message carefully that I don't think your Dielectric grease application is creating contact and electrical distribution issues. The Emerson centrifugal contacts and mechanism are brass/copper. They are not going to corrode, rust, whatever. There is no real need for grease, but if you feel better putting it on, have at it with my blessings. 🙂

Can we get back to the rotor issue now? 🙂

[Tim Babcock]

2 hours ago, Russ Huber said:

Tim, all the dielectric grease concern aside, when you engage power on your video, you can hear the start/run windings energize. How snug is your rotor as far as end play? Is there much if any end play (rotor play back and forth) on the bearing shaft. 

The end to end play is about 1/16 inch or less. I tried one more washer and it was too tight. Pulled it out and the play is about 1/16 or less

[Russ Huber]

I wish I was close enough to pop in and get my eyes and mitts on it. This doesn't help you much, I know. Watching the video it doesn't "appear" the rotor is at any point in contact internally with the stator. You could try taking one of the fiber spacers out in back of the rotor if you have two in the back first, or one in front if you only have one fiber spacer in back. This will give the rotor a little more play in the field. Then juice it and see if it takes off. 

[Ryan Blazei]

I would check the start winding for any opens. Start by testing resistance through the copper contacts at the back. It is split so probe both sections. Should be 10 or more ohms. If you don’t get any readings there is a broken connection that may require a rewinding.

[Nicholas Denney]

11 hours ago, Tim Babcock said:

I don't agree. I was an Electrician for several years. We used dielectric grease on many connections. I use it on all my fan switches. Never had any issue.

Leave your experience as an electrician behind, this is the work of a motor technician. There is little to no overlap between the two professions!

There are only two possible reasons why your motor is binding on you. 

-The stator is not fully seated AND secured. The nuts on the motor studs should have washers under them and be tightly snugged. The studs also need to be adequately threaded into the housing. 

-The housing has a hairline crack or more, allowing it to flex, moving the stator and binding the motor. 

In my opinion, you should bring this fan to a meet or give it to someone experienced enough to properly work on it. 

[Tim Babcock]

5 hours ago, Ryan Blazei said:

I would check the start winding for any opens. Start by testing resistance through the copper contacts at the back. It is split so probe both sections. Should be 10 or more ohms. If you don’t get any readings there is a broken connection that may require a rewinding.

Thanks, I will check that. If the starter winding is a broken circuit than what is the fix? New donor stater or rewinding?

[David Allen]

Tim, have you measured resistance at the start switch? In other words, take the rotor out first, and then put the meter probes on the two halves of the start switch? This should show a closed circuit with the combined resistance of the start and run windings.  If this circuit is "open" or "KΩ" or "MΩ" then there is a problem. By measuring in the manner I suggest, it will allow you to detect problems in the winding and wiring to the centrifugal switch as well. 

At risk of encouraging drama (which I hate) I want to comment on the dielectric silicone grease. It is a good idea on the sliding guides of the moving parts on the rotor. It will cushion their movement and make them quieter and avoid wear. My concern has to do with mechanical properties of the grease. Due to the relatively large diameter and high sliding speed of the electrical contacts, there is a chance the grease will form hydrodynamic film between the parts due to the motion. This wouldn't prevent the switch from closing when the fan is stopped, but might cause some interference with it when the motor is spinning but not up to speed. I don't think it would cause your "total no start" problem, however. Once you get the motor working, if there seems to be an excess of sparking during the spin-up you might want to remove all but the thinnest coating of this from the switch contacts. But it may not matter. Just be aware it could have an effect. I learned this the hard way with the shorting necklace on repulsion-start inductinon motors. It will absolutely cause problems there. 

[Tim Babcock]

39 minutes ago, David Allen said:

Tim, have you measured resistance at the start switch? In other words, take the rotor out first, and then put the meter probes on the two halves of the start switch? This should show a closed circuit with the combined resistance of the start and run windings.  If this circuit is "open" or "KΩ" or "MΩ" then there is a problem. By measuring in the manner I suggest, it will allow you to detect problems in the winding and wiring to the centrifugal switch as well. 

At risk of encouraging drama (which I hate) I want to comment on the dielectric silicone grease. It is a good idea on the sliding guides of the moving parts on the rotor. It will cushion their movement and make them quieter and avoid wear. My concern has to do with mechanical properties of the grease. Due to the relatively large diameter and high sliding speed of the electrical contacts, there is a chance the grease will form hydrodynamic film between the parts due to the motion. This wouldn't prevent the switch from closing when the fan is stopped, but might cause some interference with it when the motor is spinning but not up to speed. I don't think it would cause your "total no start" problem, however. Once you get the motor working, if there seems to be an excess of sparking during the spin-up you might want to remove all but the thinnest coating of this from the switch contacts. But it may not matter. Just be aware it could have an effect. I learned this the hard way with the shorting necklace on repulsion-start inductinon motors. It will absolutely cause problems there. 

I removed the grease from both the centrifugal and copper contacts. It made no difference. I think I have found the issue. I get no reading at all on the inner copper contacts. I tried it in several spots and nothing. So it would make sense that the starter coil is or has some issues. I guess I will take the movement out and see if there is anything I can see where the circuit is broken. If not not sure what the options are. New coil?

[Russ Huber]

On 1/31/2024 at 5:41 PM, Tim Babcock said:

I have the Emerson fan back together for the most part. It runs without the front cover on but when I put on the cover and it goes over the bolts a bit tight but not horrible the rotor gets stiff. 

Tim, 

I was hoping there was some stator alignment issue. That could be made right eventually. An open in your start winding with no obvious broken wire in the circuit requires a stator rewind, or stator replacement. I hope you can spot a repairable open. Good luck.

[Michael Rathberger]

You might check the wires themselves or the solder connections for continuity before you give up on the stator....

[Ryan Blazei]

It seemed that would be the case. A motor that cannot start on its own is typically an issue with the start windings. I wouldn’t think the motor cover would influence the stator much unless it was loose in the motor housing. Like other said, check the solder connections to the copper contacts and for any loose wiring. Otherwise a rewinding is needed. I can help with the motor rewinding if no one else is available. Best of luck 

[Tim Babcock]

4 minutes ago, Ryan Blazei said:

It seemed that would be the case. A motor that cannot start on its own is typically an issue with the start windings. I wouldn’t think the motor cover would influence the stator much unless it was loose in the motor housing. Like other said, check the solder connections to the copper contacts and for any loose wiring. Otherwise a rewinding is needed. I can help with the motor rewinding if no one else is available. Best of luck 

I have some family coming in next week and it will be busy for me. Won't have much time to chat or post. But I would be very interested in what you would charge to to a rewinding on this. The week after next I will tear it down and look for anything easy to repair, loose wire, broken wire ect. Then if I can not repair it I can have a number to give to the owner and see what they want to do. Thanks for the offer. My email is dogon2u@gmail.com I check that more than forum notification. Thanks

[Paul Michael]

On 1/30/2024 at 8:17 AM, Tim Babcock said:

I had to drill and put a self tapping screw in the spacer. It was in tight. After I pulled the spacer the stater tapped out with the pipe easily.

(From your previous post.) That was a bit of extra work, I can't imagine why you couldn't have just pried it out.

But no matter: Your stator is either shifting, or if not tightly seated at rear, possible being cocked off plane as one side tightens down. Probably the first.

I'd go back to square zero. Take the stator back out, and remove all 4 studs and check for straightness. If they are being moved even a tad off their central axis to fit and tighten the cover, that could cause a related small shift to the stator alignment/centering, and bind the rotor. Recenter once the straightens is determined or corrected. The cover should NOT push and studs at all if they are aligned. 


[I wrote this in the morning and abandoned it... Now I see questioning whether the stator windings are acutely bad.... What???? You said it 'runs ' with the cover off. Is It NOT running? Does it bind if spun by hand, or only when power is applied? From your initial description, this still sossunds like a mechanical bind. I haven't had any of my 1500s open in a long while, so I can't compare except from (severely lacking) memory.]

 

Edited February 2 by Paul Michael

[David Allen]

6 hours ago, Tim Babcock said:

I removed the grease from both the centrifugal and copper contacts. It made no difference. I think I have found the issue. I get no reading at all on the inner copper contacts. I tried it in several spots and nothing. So it would make sense that the starter coil is or has some issues. I guess I will take the movement out and see if there is anything I can see where the circuit is broken. If not not sure what the options are. New coil?

It does sound like there may be a problem in the stator. It may be a wiring problem, but be prepared for the possibility of a rewind being necessary.

[Tim Babcock]

1 hour ago, Paul Michael said:

(From your previous post.) That was a bit of extra work, I can't imagine why you couldn't have just pried it out.

But no matter: Your stator is either shifting, or if not tightly seated at rear, possible being cocked off plane as one side tightens down. Probably the first.

I'd go back to square zero. Take the stator back out, and remove all 4 studs and check for straightness. If they are being moved even a tad off their central axis to fit and tighten the cover, that could cause a related small shift to the stator alignment/centering, and bind the rotor. Recenter once the straightens is determined or corrected. The cover should NOT push and studs at all if they are aligned. 


[I wrote this in the morning and abandoned it... Now I see questioning whether the stator windings are acutely bad.... What???? You said it 'runs ' with the cover off. Is It NOT running? Does it bind if spun by hand, or only when power is applied? From your initial description, this still sossunds like a mechanical bind. I haven't had any of my 1500s open in a long while, so I can't compare except from (severely lacking) memory.]

 

There are two issues. One is starting up.With the cover of the motor hums and does about a 1/4 inch turn but will not run unless I turn the rotor by hand. The other issue is that it binds up when the cover is put on. I am not really worried about the cover issue. I will try either boring out the cover holes or bending the studs. But I don't want to mess with it until I have the stater repaired and it is running right.

[Paul Michael]

1 hour ago, Tim Babcock said:

There are two issues. One is starting up.With the cover of the motor hums and does about a 1/4 inch turn but will not run unless I turn the rotor by hand. The other issue is that it binds up when the cover is put on. I am not really worried about the cover issue. I will try either boring out the cover holes or bending the studs. But I don't want to mess with it until I have the stater repaired and it is running right.

Ah! I must have missed that further information somewhere  in the thread... I though I read that it 'RAN' with the cover off (unassisted). That's a bummer. Yes, assuming the centrifugal start is functioning, and you have measured and found a problem with the start windings, unless it's a repairable fault on wires outside the windings, a rewind, is the proper way to go. 😬🙁

[Marc Sova]

On 2/2/2024 at 5:48 PM, Tim Babcock said:

There are two issues. One is starting up.With the cover of the motor hums and does about a 1/4 inch turn but will not run unless I turn the rotor by hand. The other issue is that it binds up when the cover is put on. I am not really worried about the cover issue. I will try either boring out the cover holes or bending the studs. But I don't want to mess with it until I have the stater repaired and it is running right.

Don’t drill/bore out the cover holes. That is not a proper fix. If this were a common 29646 or something no problem…but this fan does not come along every day.
   There’s definitely something going on in terms of the stator alignment relative to the housing (and hence relative to the rotor). Best to always take a good close up pic of where that original brass shim was at and reinstall it the same way. 
   Yeah the speeds won’t be that noticeably diffent at all with the blade off. Hope you don’t need a stator rewind but that’s probably the case. 
   

[Lane Shirey]

Try removing the rotor and then use a dental mirror and flashlight to look behind the stator, specifically where the bosses are that center it in the opening. Wiring might be preventing it from being seated properly or you might spot some other problem.