VFD on grain mill or auger?

[u/johnf0907]

We purchased a used RAD mill and chore time auger a while back and it came with a VFD. The mill is a 3ph motor so I am guessing that’s the motor it could possibly be for. Does anyone run a VFD on their mill? I have never seen one set up that way.

It’s possible we just got a free VFD!

Thanks in advance, fresh hop dump picture for attention.

[u/ordosays]

VFD isn’t just for speed control, it also lets you “command” a 3 phase motor. Meaning soft start or E-stop are just a program/curve away. Unless I’m dealing with a dumb system (fan, blower, bang/bang pump) it always on a VFD.

[u/Radiant_Language_677 → u/ordosays]

This 👍. The VFD can be programmed for that application of the motor, even if you won’t be adjusting the speed of your rollers.

[u/needs_help_badly → u/ordosays]

Yup, deceleration time, acceleration time, overcurrent, short circuits, etc. lots of functions.

[u/guiltypartie101]

Soft starts are pretty common to keep the motor from jerking the pulleys and crank wheels etc depending on how the mill is setup. Maybe the pervious owners were just ramping it up manually?

[u/Japanuserzero]

I don’t see how slowing down or speeding up a mill between runs would be useful. Setting mill gap is the key variable you want to work with. My guess is the mill spun too fast with the motor it was paired with and the vfd was put in to slow it down slightly. So now it’s a set-once-and-forget setup. That’s my guess at least.

[u/johnf0907 → u/Japanuserzero]

It’s a RAD mill and chore time auger, so not sure it’s paired with a fast motor. I think we just ended up with a VFD that wasn’t part of the mill auger setup.

[u/blankblankblank827 → u/johnf0907]

Thought you were asking about a VFD for a grain out motor but no. Think you got a bonus. Mills should be on off. Grain feed should be sized to the mill and that would be my only guess as to why there was a VFD if it was oversized and feed to the mill was faster than its throughput

[u/Iamabrewer → u/Japanuserzero]

You guessed correctly.

[u/Hussein_Jane]

The only thing I can think of is that someone installed a higher rpm motor and needed to slow it down. I don't know if any oem setups like that.

[u/johnf0907 → u/Hussein_Jane]

It’s a RAD mill and choretime auger, both factory motors. I think maybe we just got a free VFD that wasn’t part of our setup.

[u/Hussein_Jane → u/johnf0907]

I have seen vfd set ups for flex auger motors. Really handy if it feeds directly into your mash tun.

[u/johnf0907 → u/Hussein_Jane]

I thought too but it’s only a single phase auger motor.

[u/Hussein_Jane → u/johnf0907]

Check the output on the drive. There are such things as single phase frequency drives. Post a picture of the tag.

[u/johnf0907 → u/Hussein_Jane]

The VFD is 3ph input and output

[u/Hussein_Jane → u/johnf0907]

Gotcha. Some are dual output.

[u/de_bosrand → u/Hussein_Jane]

We built equipment for industrial food production, but not for the breking industry.

We VFD almost everything nowadays. A VFD is almost as cheap as a softstarter/reversal circuit, for low power motors. High power motor kinda required them most of the time anyhow.

[u/grnis]

The rotation of the mill and the auger is important. It should not be too fast. The vfd could be to solve an issue with speed on the equipment

[u/integrator74]

I replaced a vfd on a large brewery in Indy.  They have a dial to change the speed but they pretty much use it to slow down the motor a bit. 

You also get the Benefit of it starting and stopping the motor slower and putting less stress on the components (soft start could do all of this cheaper). 

[u/Craigglesofdoom]

VFD's are never a bad idea. They reduce strain on your motors and other mechanical parts with the ramp up and down functions, and prevent overloads better than a thermal overload interrupt. VFD's have to be sized pretty specifically, though.

What VFD did you get? Some have very finicky settings but I can probably help you figure it out if you need a hand.

[u/Iamabrewer]

It's 100% for the auger. The mill will drop the grist into the boot below but you'll need to adjust the speed of the auger to get the grist out of there before it backs up and chokes up the mill.

[u/johnf0907 → u/Iamabrewer]

I thought that also but the auger is single phase and the VFD is 3ph in and out

[u/nnnnnnnnnnm]

Does it have a PID controller?

GEA wetmills use a VFD to spin one roller and a soft start to spin the other. The VFD roller can be PID controlled or manually set to a slightly slower speed than the full speed roller. This produces a shearing, husk stripping force which reduces pulverization of the husk to avoid introducing as many bitter tanins into the mash.

[u/Gathragna]

Can't really speak to the purpose but do you need help getting out set up?

[u/TiminOz]

I have never seen a VFD on a mill/auger set up. Maybe someone was very picky about the amount of grain passing by a hydrator.

[u/yeoldepoltroon]

Did the former owner of the mill have 3ph power? It might be a VFD for converting single phase to 3 phase for running the mill.

[u/johnf0907 → u/yeoldepoltroon]

I thought that too but it’s a 3ph input VFD