Calculate the Speed of a Conveyor in Feet\Min from a known Frequency.

[OkiePC]

1760 * 1 / 3 (Gearbox) = 586.7 rpm * (3.14159 * 2) (pi * D) = 3686 ft/min

This takes no account of: motor slip, belt slip or belt thickness.

Nick

1760 RPM base speed includes 2.2% slip, which appears to be accurate enough to meet the needs of the OP...

 

[Bruce99]

conveyor speed

First rule- never measure the coveyor speed by the drive running the belt. It will never be the same.

Second rule- the take-up pully or a nondrive centering roll or any roll with a positive contact in all load stuations should be used.

You can use a pulse type encoder or a wheel type prox encoder or some other design that suites your PLC. The take-up pully needs to maintain the tension on the belt so it is used is most cases. Your drawing can be used on the pully and it can send counts to the PLC for conversion to feet per min.

 

[anoop]

speed regulation using a encoder & powerflex 40p drive

guys,
i have a powerflex 4m driving a motor1(2hp,1400RPM@50HZ,GBR= 15,CHAIN ratio 0f 5/3)the motor1 rpm after all reduction is 56 RPM
I also have a powerflex 40p drive running a motor2(.25hp,1370rpm @50hz,GBR 24 NO chains dirctly connected to crank of a hand pick tool).To the powerflex 40p an encoder of HVLD(line driver) type of ppr 360 output is connected
the encoder is placed in motor1 shaft of 57 rpm
i got the powerflex 40p speed as a varying thing.it is not constant it is almost near the required drive speed +-3 differences(eg if 50hz is neeeded i am geting 48.3,51.3 like that it is dancing)
my client needs a constant output from powerflex 40p
my pulse in scale value from my calculation is 6.71 but i can set only integer value in pf40p
help me

 

[Bit_Bucket_07]

Heh!

You may enjoy a sense of accomplishment from sitting at your desk and modeling the drive train and calculating the belt speed, but why bother? As many have already suggested, simply take a few measurements with a hand-held tachometer. If you don't have one, then purchase one. They aren't terribly expensive and they certainly come in handy when you're in this line of work.

Why infer when you can measure? I know... That sounds ironic when we're talking about taking measurements for a belt speed inference program. It's still the best solution though, IMHO.

 

[mastersonec]

Most VFD's provide slip compensation. So regardless of the RPM's listed on the motors name plate, when the VFD is operated at 60hz, the motor's actual RPM's will be closer to syncronous speed ( ie. 1800 RPM's ).

 

[DickDV]

At the risk of being labeled "crude", why not power down the whole thing and lay a yard stick along the belt. Now turn the motor over ten times by hand and measure how far the belt moves. Use a simple proportion to get the motor up to full speed and the belt also up to full speed. Leave the calculator in your pocket especially if 5% error is acceptable.

 

[OkiePC]

If this crank of a hand pick tool is an oscillating object, you will probably do best to only static tune it with accurate entries, and use sensorless or flux vector mode. Even so, the performance of that drive in that situation is not going to be good, and depend on how heavy the swing in motor load changes.

We bought an oscilating shaker table type conveyor that is a really nice piece of hardware equipped with a Yaskawa drive on board it's base by the OEM as standar. But, our installation location was tight, narrow, wet and steamy and hard to access, so we used existing PF40 and wiring instead and could not get anywhere close to as steady a speed as what the OEM Yaskawa set up could do on other conveyors of the same design in other locations. I had to go up a notch in drive size, too, to be able to go above 40Hz without faults compared to the Yaskawa.

 

[JustAGuy]

Absolute simpliest method and only takes quick minute.

1. Measure FPM with handheld tach at a known Hz.
2. Make note of the Hz and the FPM.
3. Divide tached FPM by tached Hz which will give you a Hz to FPM ratio
4. Actual FPM = Actual Hz * Hz to FPM Ratio

Example: Motor tached at 60 Hz results in 45 FPM.
45 / 60 = .75
So if the motor is being told to run 33 Hz then.
33 * .75 = 24.75 FPM

Accurate enough for me, especially if it is only for display purposes.

 

[seppoalanen]

1760 * 1 / 3 (Gearbox) = 586.7 rpm * (3.14159 * 2) (pi * D) = 3686 ft/min

This takes no account of: motor slip, belt slip or belt thickness.

Nick

Good points!

multiplier=Pn/P*f/60Hz, no thickness.
With fielbus ctrl 0.5% accurary.
With analog ctrl, forget this!

 

[bright676]

Why no just use a tachometer?

 

[seppoalanen]

Why no just use a tachometer?

Tachometer is not needed with Induction motor if VFD & fieldbus is used,
you can easily get Power, output Frequency etc. via fieldbus.
With contactor case we usually don't know the power.
Induction motor's slip is almost linear from Pn to "zero".