Trash

[ptonsparky]

Then why not just double the gear ratio as you suggested but NOT change the present motor?

Double your torque, double or triple your output HP with no need to pause for concern? See my post #10 again....

Dropping the the drag speed will also double or triple my fill time. 40 minutes to 80 or 120 takes a good hunk out of the day.

More HP. Just don't know how much is enough.

 

[mike_kilroy]

Dropping the the drag speed will also double or triple my fill time. 40 minutes to 80 or 120 takes a good hunk out of the day.

More HP. Just don't know how much is enough.

I thought my post might have confused you.... you will fill IN THE SAME TIME AS WITH PRESENT RATIO.

if you do as I suggested, double the gearing, you get double torque. But since you are only running at 20-40hz now, you certainly can run the same present motor and vfd at 40-80hz instead. So your fill rate REMAINS THE SAME. You simply get 2x the present torque from your present motor and present vfd and do the fill in the same time as now. FREE - it is just tweaking the gearing to better match your equipment and requirement.

(To be exact, you will get 2x the torque from new 40-60hz then it drops as speed goes above 60hz, but it is still a major improvement.)

 

[ptonsparky]

I thought my post might have confused you.... you will fill IN THE SAME TIME AS WITH PRESENT RATIO.

if you do as I suggested, double the gearing, you get double torque. But since you are only running at 20-40hz now, you certainly can run the same present motor and vfd at 40-80hz instead. So your fill rate REMAINS THE SAME. You simply get 2x the present torque from your present motor and present vfd and do the fill in the same time as now. FREE - it is just tweaking the gearing to better match your equipment and requirement.

(To be exact, you will get 2x the torque from new 40-60hz then it drops as speed goes above 60hz, but it is still a major improvement.)

My 20-40hz and 40-80hz is not the problem. The problem is the 120 Hz I need to fill at a decent rate.

My motor guy keeps saying I cannot run his 4 pole motors over the 1750, or 2330 for one of them. VFD rated motors. I have customers that have bigger motors running at 120 and understand that 180 is possible. Yes, the torque goes to hell in a handbasket from what I understand.

We are going with double the gear ratio and the 2330 rpm rated 2 HP motor. I wont feel so guilty about driving it a bit faster if need be.

 

[mike_kilroy]

Still confusion on your or my part; I am not suggesting having to run at 120hz.

Let me try this:

Your present acceptable fill rate (time to do the job) is at 20-40hz output on vfd. Is that correct?

 

[mike_kilroy]

your issue is just that the present system overloads/stalls/overheats/shutsdown due to excess load at the speed you want to run, right?

It sounded to me like even if you had a zillion hp motor the process makes the max speed the present 20-40hz max, right?

 

[ptonsparky]

your issue is just that the present system overloads/stalls/overheats/shutsdown due to excess load at the speed you want to run, right?

It sounded to me like even if you had a zillion hp motor the process makes the max speed the present 20-40hz max, right?

No, the inlet to.the drag plugs with trash. We need to open that inlet to prevent trash plugging. Opening the inlet results in an overloaded drag motor. A 2 hp doubles my torque. Increasing the size of one sheave doubles it again. I will compensate for more product in the drag by adjusting the rpm of the motor so the end result is 1000 bu/hr which is the limit of my production, or 60hz at the original ratio and gate opening. I do not know how much more grain will flow with a wider gate so to get my 1000 bph at fill, my hz may be as high as 120. That is unknown. My original operational or production speed was 20-40 hz. Fill was at 60. That translates to 40-80 and 120 if everything is linear. Doubtful.

I was up to trying your suggestion on the v/hz change but the owner said change motor too.

I will know in an hour how the hp change works. Two days before the sheave is in.

I do appreciate any and all answers even if it is suggesting that that I am suffering from HUA Syndrome. Been there before a nd will again.

Thank you.

 

[mike_kilroy]

so the end result is 1000 bu/hr which is the limit of my production, or 60hz at the original ratio

I misunderstood. Thank you for clearing that up. So IF you have enough torque, then you can increase rate to 60 (or 120hz if double gearing).

Now just for another anecdote on continuing your v/hz up to 460v@120hz on your inverter duty motor. Since your motor is rated for vfd spikes, then doing the 230v wiring and using vfd to 460v@120hz should not hurt the windings. We have hundreds of spindle motor applications in the field from the early 1990's still running perfectly find this way. As for running someone's motor not rated for 2x the speed at that mechanical speed, that is another story altogether and worth worrying about. I have been told MANY times over the years by various generic motor mfgrs that they use DIFFERENT bearings in their 2 pole motors than their 4 pole motors - kills the idea that most people think (since a 2 pole motor goes 2x as fast, it has the same bearings as the 4 pole motor... - NOT necessarily true).

 

[Kermit]

Drags

Drags

A drag will be tough to make work.You cannot restrict feeding because of plugging. Unless drag is really oversized it will not work. A slow drag is like a bulldozer at every paddle. Use a short auger to feed drag. The auger will set the rate of feed. Make sure casing is big enough to pass obstructions. Lots of internet info to size an auger.

 

[kwired]

What is the drag feeding? Can it take the increased flow rate you are going to introduce?

Have to assume you are supplying a mill or other process that needs fed at a specific rate, if just filling a bin or hopper this discussion is somewhat pointless unless poorly designed drop tubes or something else like that can plug up from too much flow.

 

[ptonsparky]

The drag feeds a leg. The leg drops into a large mixing auger. We will not supply the leg with any more than it can handle or can be taken away by the mixing auger. Not gonna happen.

The problem was getting enough product to the leg. The keyword being "was". The gate is now open.
I am running the 2 HP at its max rpm with the resulting drag speed of about 30 rpm vs the 39 it was before. Most of the time it will be somewhat less.

 

[kwired]

The drag feeds a leg. The leg drops into a large mixing auger. We will not supply the leg with any more than it can handle or can be taken away by the mixing auger. Not gonna happen.

The problem was getting enough product to the leg. The keyword being "was". The gate is now open.
I am running the 2 HP at its max rpm with the resulting drag speed of about 30 rpm vs the 39 it was before. Most of the time it will be somewhat less.

A leg is not the item you want to plug or have trip on overload, I agree.

I take it even though speed is less you are moving a higher volume with the gate opened further, and probably was not large enough motor to start with if you want to give the leg all it can handle.

Hp is work over time :happyyes: