Interesting afternoon

[ptonsparky]

Customer ordered an auger that was designed to handle 8000 bushel of dry corn/hr. I was to set up the service. 480v. Auger came sans motor. OK, order a 25hp as per mfg specs. Instructions for tractor driven unit says start at slow speed until auger fills. OK, order a 25 hp VFD for speed control. Started it up today and there is no way this system can handle wet corn. We had to drop it back to 30hz just to keep the amps down. Now mfg says use 30hp. Motor will be here tomorrow, VFD on Thursday.

Will 20% increase in torque really help that much?

Customer now has several thousand dollars in spare parts.

 

[bradleyelectric]

I'd say that would be a question for the manufacturer but.....

apperently it's a guy named fred with a welder and no engineer.

Then again they may be telling you the differnce in dry corn and the added weight of 8.27lbs per gallon for water.

 

[SEO]

Sounds like an expensive trial and error.

 

[mivey]

Who spec'd the auger, the farmer or a sales rep?

 

[ptonsparky]

Feedlot told auger mfg what they wanted to do. Mfg had admitted to not making one that large before, but were willing to give it a shot. PTO driven is there norm.

Large grinder with 575hp diesel capable of 6000+ bushel of corn per hour and we are feeding it with 3K if lucky. How about a 6 week harvest instead of 3?

During the first stages of planning it was all "how much" now it's "when".

 

[LJSMITH1]

What about using a gear reduction with the 25hp motor? The max RPMS will be reduced, but you might have plenty of torque to move the wet corn.

There might also be an option to go with an extra-high torque motor. That could only be determined by the face/shaft specs and environment/space.

If max RPMS are needed, then the primary way to do it is with more HP. You can only do this assuming the rest of the mechanical drivetrain can handle the increased torque.

 

[ptonsparky]

We rigged up a light to come on when the motor hit 100% torque via the relays on the drive. That corresponded pretty well with FLA. In the 1 1/2 days they used the 25hp they got to about 4k bu per hour. The 30hp increased it to about 5.5k per hour right away. They are happy, at least until the end of next week, then I'll be happy.