Need advice regarding an electric motor

[Comosicus]

Hi,

I need a bit of advice about an electric motor that is giving me a lot of trouble. It is the motor for the fan controlling the airflow in a natural gas heater (that provides both house heating and hot water). Here's the problem:

The motor receives power (it hums and vibrates), but the rotor does not start spinning on it's own. It feels like it's stuck. I need to give it a push with a screwdriver so that it starts moving. But once it starst spinning, if I cut the power, there close to no resistance to the rotation, so I don't think it's an issue of lubrication.

The really weird thing is that it happens more often in the evening and during the night than during the day (so I guess there's something related to the ambient temperature as well). I already payed for a repair a few weeks ago and have yet to recover my money from the landlady so I am reluctant to call the tech guy again.

Funny stuff is that it worked the last three weeks without problems. But, just like last time, it started to break down just as soon as I began my vacation time. I think it hates me

If needed I can track the schematics for the boiler and link them here. And one last question: With the motor being powered up, but unable to spin, is it possible to break down completely? It happens so during the night, when the heat is turned on. As the water reaches the desired temperature, the fire shuts down. But when it needs to ignite again the fan fails and keeps buzzing all night till morning.

Any advice would be really appreciated. Thanks in advance

[fordlltwm]

It's most likely to be the run / start switch on the motor that's sticking, it should centrifrugally switch from start to run and back again but sounds like it's stuck in run, schematics would help to diagnose further.

[Comosicus]

Here is the electric scheme from the manual. I only found a Romanian manual and I translated the legend myself. Hope it makes sense:

[fordlltwm]

I don't suppose you check on the motor for the fan to see if it's got a ~1 inch can strapped to the side of it? The manual doesn't suggest whether it's capacitor start or not.

[Comosicus]

I'll open the cover today and take a few pictures. I need to jump start it for a bath anyway.

[The Duchess of Zeon]

Coefficient of static friction is usually higher than kinetic friction, it's possible for an object to resist motion in a static state but spin free once no longer in a static state, so the bearings may in fact be the problem. I will think of other things tomorrow.

[Comosicus]

I opened it today, but it only worked for a couple of minutes or so and nothing made it start afterwards. I can push the external blades as may times as I want, but it does not keep moving. I took some pictures of the motor, that you can see below. BTW I could see no capacitors whatsoever.













I can only be glad that for the next week the minimum temperature will be about +6 Celsius. I don't intend to notify the landlady until I receive the money for the first repair. Otherwise I can kiss them goodbye.

Thanks again for helping me.

EDIT: Please ignore my ugly mug

[Sky Captain]

I have an old electric lawn mover that had similar problem - I had to turn it on the side, switch on the power and push the blade with stick to start it spinning. It was a busted capacitor, once replaced it worked ok.

[Comosicus]

I have an old electric lawn mover that had similar problem - I had to turn it on the side, switch on the power and push the blade with stick to start it spinning. It was a busted capacitor, once replaced it worked ok.

I've found too about the capacitor problem. But as you can see in the pictures there's nothing resembling a capacitor there. And this morning, it only ran like a couple of minutes then I couldn't move it at all with all the pushes in the world. It just buzzes and my layman feeling is that the fan engine burnt out.

[The Duchess of Zeon]

This honestly sounds pretty similar to what happened with the electric motor on the natural gas furnace heater of my old home... The motor burned out as a result of bad bearings, with symptoms like you described with the fan not initially turning despite the motor coming on, and giving it a little pull getting it to spin freely. With the additional symptoms you have just reported now, the electrical motor has unquestionably been burnt out and needs to be replaced. You will also however need to get the bearings re-packed or outright replaced with new ones (better yet with graphite solid lubrication) as it sounds like almost exactly the same set of symptoms. Main difference is that motor was operating a belt driven fan and I gather this isn't, which means it could be something else, but I'm fairly confident it isn't.

[Comosicus]

I will definitely do nothing of those. It's the landlady's job to do it. And maybe it wouldn't have happen at all if she would have done the periodic maintenance (as written in the manual). I already payed for an intervention at the beginning of December and was promised I will get the money back as deduction from January's rent. I'm gonna wait for that to happen first before I notify her about this. Especially as I have already gave the one month notice that I'm severing the contract and moving away. I already foresee issues when it comes to returning the guarantee deposit. With the current crisis she's not gonna find another tenant soon, especially at the price she wants.

Last time I payed 173 euros for a botched intervention (the tech guy had to come two more times and ended changing an air valve). It worked for three weeks only when this happened. Funny stuff was that the first time it broke I was also having a minor vacation. Maybe it's my magnetic personality that wreaks havoc with the damn thing. Or accidental magic. Why did I not get my Hogwarts letter? Heh, or maybe the boiler it's indeed Gandalf in Moria: "Run, you fool!"

The point is: any intervention is bound to cost at least about the same, considering it also needs replacing the fan motor and I have the nasty feeling they don't sell it separately but will have to replace the entire assembly. The downside is a Christmas without heat and hot water. I hope the weather will stay mild until Friday, when I get my salary. Then I'll be able to buy an electric heater and move on over the last month I'll be staying here.

[Comosicus]

End of the year updates: we survived the last week using a halogen heater and boiling water in pots to fill the bathtub. Today we got a tech from a different company and it appears that the fan engine works just fine, but the axle got a bit loose and gravity made the entire turbine fan to fall down from its place and rest on the carcass. The direct contact friction was too much for the motor to handle even when push-started.

A short term solution was achieved by pushing the fan to its place, but it's bound to fall down again as the movement is too loose and the vibrations will only accelerate the process. For now we are able to get some heat and took the last leisure bath of the year. As soon as they get a replacement turbine they'll come and replace it properly (and the price is the same as the first unfortunate intervention). Till then it's back to the old "push the blades to kick-start".

Morale(s) of the story:
1. Not always the emergency numbers you have will give you the best services (the first company said they don't deal with replacement parts)
2. Between "damned if you do, damned if you don't", choose to do it. If we elected to leave things as it is, most probably the owner would have ended charging the problem agains our deposit money. She might still do it, but at least we'll be warm for the last month.

Thanks again for the support. Happy New Year to all of you!