High temperature motor - where to buy?

[knighty]

I have a big dehydrating machine at work. Internal fan ran from a shaft from center of machine out through the wall to a pulley and then belt driven

But it's always eaten though the bearing at the pulley quickly.... Tried everything it still kills them

Decided to change it around, flange mounted motor on the side of machine with a flexible coupling to direct drive the shaft...

But it was noisy as hell, bit of investigation and the original shaft was too far off straight (I'd lined new motor up with the old shaft)

I guess shaft out of line was ok because it was belt driven, but no matter the belt tension it'll have been trying to twist the shaft back straight and killing the bearings


Lots of pondering later I've fitted the motor inside the machine with the fan direct mounted to motor

Problem is it's 60'c in there... Already had the motor with no other use so willing to waste it...


Google says high temp motors are a pretty common thing... But I can't find any to buy?

3 phase, 1.5kw, 2800rpm

Anyone know where I should look?

 

[Erie Fred]

Ovens use them, try an industrial oven supplier.

FWIW all I have ever seen is belt drive.

 

[gaz1]

most ive seen are belt driven as heat and motors they kill motors for fun

hence the reason why most motors are outside of the housing and bearings are used to turn the fan

its also the method id use when sending high heat through pipes in excess of up to 500c or higher

 

[Erie Fred]

I have seen direct drive motors, but have a very long extended shaft.

 

[skotl]

I’m not sure that 60C would count as “high temperature” so you may be overthinking it

 

[Brad93]

I have a big dehydrating machine at work. Internal fan ran from a shaft from center of machine out through the wall to a pulley and then belt driven

But it's always eaten though the bearing at the pulley quickly.... Tried everything it still kills them

Decided to change it around, flange mounted motor on the side of machine with a flexible coupling to direct drive the shaft...

But it was noisy as hell, bit of investigation and the original shaft was too far off straight (I'd lined new motor up with the old shaft)

I guess shaft out of line was ok because it was belt driven, but no matter the belt tension it'll have been trying to twist the shaft back straight and killing the bearings


Lots of pondering later I've fitted the motor inside the machine with the fan direct mounted to motor

Problem is it's 60'c in there... Already had the motor with no other use so willing to waste it...


Google says high temp motors are a pretty common thing... But I can't find any to buy?

3 phase, 1.5kw, 2800rpm

Anyone know where I should look?

Send me a PM i'll pass on some details

 

[Sergei Slovenija]

An additional fan for the electric motor is a standard solution for such cases. The original plastic impeller, where the blades do not have an angle of inclination, is a poor solution for efficient cooling.

 

[Agroshield]

These people have some good information:

How do I classify the temperature limits of an Electric Motor?

BS EN 60034-1 classifies the temperature limits (and rise limits) of insulation materials. It specifies the maximum permissible temperatures that the various classes of insulation materials can withstand.

www.quantum-controls.co.uk

As an alternative to a high temperature motor, even if only for price comparison, consider a normal one of higher wattage and derate it (article above suggests 80% power output for 60 degrees).

 

[knighty]

I’m not sure that 60C would count as “high temperature” so you may be overthinking it

Me too... But figure a high temp motor probably isn't that expensive, it's an expensive machine, one load of stuff in it will be worth more than the motor cost

 

[optima21]

think you can also get motors with thermistors/thermocouple in windings so that you can monitor the internal temperature of them.

 

[Brad93]

As i said in my PM, it's more than likely an alignment/vibration issue causing failure.

Most greases work good to about 85°C

 

[knighty]

I replaced the bearing on the fan end of the shaft once - as a matter of course when I replaced the bearing on the other end of the shaft, but it didn't need it

bearing on the pulley side of the shaft is outside of the machine in ambient air, probably gets warm to the touch through heat transfer along the shaft but it's not hot (and this is the bearing that keeps dieing)

I guess they pulley could be out of balance, there's was no noticeable vibration/noise from it

I spent a long time getting belt tension right to make sure it wasn't that killing them - plus if it killed all those bearings on the pully side I'd expect it to have been hard on the motor bearings too which are still good

it's running great with the motor inside the machine just trying to go belt and braces with high temp motor - or at least get one and have it on the shelf ready for it it's needed

 

[Brad93]

have you got any pictures or a drawing of the layout. If the belt is flexing the shaft then you need another bearing to support the shaft or a bigger shaft

 

[knighty]

I've dumped the bearing and the shaft moving the motor inside the machine and direct mounting the fan to it

that's why I'm asking about high temp fans

it was a 25mm shaft with the pulley mounted a few mm away from the bearing that kept failing

1.5kw at 2800rpm ish, the shaft was more than big enough


there was no real noise/vibration or any sign that something was wrong, just a pile of dead bearings

whatever it was I didn't really care, I'd rather the fan be direct mounted to the motor anyway, no idea why they didn't do that to start with,

with the old motor and belt out of the way, which were mounted on the top of the machine it gives room to re-jug stuff up there


looks like it was build buy salesmen not engineers - which would suit the price tag of £85k new (I didn't buy it new!)

I thought the machine did something fancy but it doesn't.... I could have build a better (but not as pretty) machine for sub £3k (I'd have never bought it if I'd known)