Stir plate need a push

[Ski12568]

After I glued the magnets on the fan, every time I plug it in I need to shake the box just right to get the fan moving. I tested the fan before I installed it in the box but I still needed to give the fan a push. It works great once it starts spinning. Any thoughts? New fan? Weaker magnets?

 

[MaxStout]

This is happening just whenever you plug it in--without a flask and stirbar?
Is it a single magnet (i.e., hard drive magnet) or two button magnets?
Are the magnets balanced?
Are the magnets rather heavy and perhaps too much mass for the fan to get rolling?

I'm assuming you tested the fan before you attached the magnets and it turns OK?

Edit: One more question...are you applying sufficient voltage to drive the fan?

 

[day_trippr]

Did you glue the magnets directly to the fan blade hub?
Some fans are more sensitive to magnetic flux playing havoc on the motor.

If you attached the magnets to the hub you might try removing them, gluing a big steel washer to the fan blade hub, then position the magnets on that and glue them in place once you have everything balanced and the spacing right for your stir bar...

Cheers!

 

[Ski12568]

This is happening just whenever you plug it in--without a flask and stirbar?
Is it a single magnet (i.e., hard drive magnet) or two button magnets?
Are the magnets balanced?
Are the magnets rather heavy and perhaps too much mass for the fan to get rolling?

I'm assuming you tested the fan before you attached the magnets and it turns OK?

Edit: One more question...are you applying sufficient voltage to drive the fan?

With or without the flask.

Yes, it spins fine once it is started.

They are not heavy but really strong.

Yes it was tested and runs fine until I glued the magnets. Just needs to be lifted and a tap or two on the table to get going.

9V .5 amp power hooked up to a computer fan.

 

[Ski12568]

Did you glue the magnets directly to the fan blade hub?

Some fans are more sensitive to magnetic flux playing havoc on the motor.



If you attached the magnets to the hub you might try removing them, gluing a big steel washer to the fan blade hub, then position the magnets on that and glue them in place once you have everything balanced and the spacing right for your stir bar...



Cheers!

Yeah they are glues right to the fan, I don't think I can remove them but I have another fan I can do the washer trick to. I might try that. Thank you

 

[Ski12568]

The washer worked. Used a quarter and it's working better than I expected. Thanks