Search for a Motor

Without knowing how quickly it needs to get up to speed or how much friction there will be once it is up to speed there is know way to know.

3,450 PRM 60 Hz AC motor geared up a little will do it nicely. May be over kill, but we can't tell based on your information.

Start googling motor suppliers. That's what I'd do, then, I'm funny that way.

Get a lawn mower engine and use v-belt and pulley setup for 4k speed....

http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=toolt&th=281426

http://www.sufficientself.com/threads/upcycled-repurposed-projects-many.11661/page-10

What is that? A skeet trap that flings tires for a Vulcan Gatling gun to shoot at?

I would not want to be on a Vespa at 142 MPH!

OK then...

https://www.youtube.com/watch?v=1z43muPetNc

Charley retraced his path looking for his lost dentures. "Shouldave lef em in the glass dif morning" He muttered, dragging his bag behind.

Breaking News: Bandit seen leaving local Wal-Mart at record speed with a basket full of goodies (mostly Twinkies) on his green molbility scooter. In other news, several customers of the same local Wal-Mart were complaining about exhaust fumes on aisle 7, and the annoying high-pitched scream of an over-vamped engine.

I have a few questions?

• Is the plate balanced? If it isn't you better watch out.
• What material is it made of?
• What is the diameter of the shaft that it will mount to?
• How will it attach to the motor?
• You are going to have a centrifugal spinning wheel of death!
• And now for the biggest question....... WHY? What is the purpose of your machine?

My company tests aircraft speed sensors used on engines and landing gear sensors.

We need to construct a test bed to simulate the aircraft's taxi / landing speed and also engine speed.

The plate is to simulate the aircraft and hold the aircrafts sensor assemblies for measurement.

The maximum RPM is 5,000 and minimum is 3,000.

I see where you're going.

• Mount that sucker on a stable platform and use High-end bearings
• Set it up as a Jack-Shaft configuration with pulleys that get your ~4000 RPM from a 3450 RPM motor like Lyn suggested.
• There are engineers here that can help with the motor HP rating.
• Buy a VFD. Look on the supplier page on this forum or ebay.
• Connect it to the proper motor
• Program the VFD to spin up and spin down slowly.
• Attach your sensors and let her rip!

Thank you.

Now, as you stated, I need to know what HP to use. You guys are getting closer in providing me an answer.

I know how to construct the simulator. All I'm needing is the motor to spin this "sucker". That's why I started this inquiry.

I will be very honest with you,

There are several very talented and experienced engineers on this site that can do those equations.

Me, not so much, I don't have the formulae experience that they do.

Seeing that you work in a company that has resources, why not contact one of them and offer them a stipend for their calculations.

I'm not going to recommend any particular person because their feelings get hurt sometimes.

Just search the forum for other posts that mirror your own!

If I was going to do it by the seat of my pants, this is what I would do.

• Find the nearest 2 HP motor laying around.
• Connect it via jack-shaft and pulleys. I'm thinking a 1.5" shaft would be best too! You can turn down one end for the pulley.
• Find or buy a VFD that can control the 2 HP motor ratings.
• Power up and have fun.

If you are going to use a VFD, the motor will have to be rated for variable frequency operation. "The nearest 2 HP motor laying around" better be.

This joker is like those people that ask me for " A free estimate ". Always looking for something free.

20 questions is not my favorite game.

You have gone from needing a "motor" no mention of the type (electric/gas/LPG) that runs at 4,000 RPM spinning a plate to something entirely different.

"Sensor assemblies" leaves much unknown also.

What else have you NOT told the forum?

Or, should we just keep guessing until you give the entire bag of requirements?

Your company tests aircraft speed sensors. I'd think you'd give more detail.

An electric motor is preferred.

I was explaining what the plate will simulate. I'm not off base. Forget the sensor if it confuses you.

Sarcasm is not necessary. Although it is entertaining

I can visualize the taxi/landing (wireless) speed sensor testing as it would apply to this spinning wheel, but not the engine (turbine, recip?) speed and not for any certification.

As a curious kid, I discovered that a 78rpm record (Guy Lombardo to be accurate) would adapt to a Hoover motor shaft by means of a section of rubber tubing. Before the motor reached the unloaded speed of 17,000rpm, the stiff record disintegrated into pie shaped sections which embedded themselves in the drywall, luckily for me the plane of rotation was away from any body parts. I did notice a definite gyroscopic effect before the disintegrations. Later, I found a use for the motor as the prime mover for my coffee can mouse centrifuge experiment.

coffer Coffee can mouse centrifuge experiment.

Really, did you give the poor mouse any Dramamine?

What mouse? Seriously, we are trying to find a motor here.....

What I'm asking is if your mouse can get the OP's plate spinning at 4000 RPM from his little cage wheel?!?

Well then, if the mouse had accelerated slowly (no G-force) he probably would have lived longer.

Ummmmm...... We're not going THERE!!!!!

Though it was very funny when that posting vaporized into the nether regions of the digital dump!

I was going to propose that any gain in life expectancy would be lost in the slowing down process or was he just going to hit the brakes and live forever (as a stain on the inner surface of his centrifuge)?

I found a motor. Thanks for your help.

Awesome,

Please be careful as a spinning mass like that has a tendency to be a bit unruly!

Let us know how it works out!

kfryer58,

I apologise for the run around most folks get here. It takes some weeding out to find the useful answers.

I saw that you found a motor. Good. I just wanted to add a few small things.

Once the plate is up to speed, you only need enough power to overcome frictional losses from your bearings (and air resistance).

Most of your power draw, and therefore what you should be looking at, is on start-up. Getting the thing turning to begin with should be your focus.

You could need a variable speed drive. A motor that can turn very slowly to start. Most electric motors (that most folks deal with every day) have a hard fast start. Think about a circular saw. You need something more like a reciprocating saw.

Really, any motor with a "soft start." A 1 hp squirrel cage induction motor would do it, depending on your frictional losses.

To sum up, you will need allot of power to bring it up to speed very quickly. How much power you need depends on how quickly you want to bring it up to speed. If you can stand a slow start, you can use a very small motor. Maintaining speed only requires that you overcome the frictional losses. With good bearings, this could be a very small power requirement.

In theory, you could use a 1/4 hp motor that comes up to speed very slowly.

-A-

I agree. Besides, a slow wind up sounds more sexy somehow.

I was going to suggest the OP use a DC motor, and simply use a direct speed control, and a 1.5:1 pulley speed ratio, but that is probably an over-simplification.

OR, he could use a small air-impulse turbine as a motor, and simply use impulse to ramp the wheel up to whatever test speed is useful. All on one single shaft.

IF air not powerful enough, use a water jet pump for the impulse turbine, or disc turbine. Disc turbines will limit speed based on the air/fluid input parameters, as pressure, density, disc diameter and spacing, fluid viscosity, etc. The idea is to have a minimum Reynolds number flow (laminar) at first, then at higher speeds, the flow should be approaching the laminar-turbulent cross-over.

Yeah, go with the DC motor, unless the AC motor you found lying on its back kicking in the dust works for ya.

Use a 2-pole motor at 80 Hz with a VFD; skip the mechanical BS.

Surround it in a stout cage (or case of stout).

Are there any recommendations?
Let's see. Velocity at perimeter = 4000 rpm x π x 1 ft = 12566 ft/min = 209 ft/sec

Acceleration = v2/r = 87382 ft/sec2 or 2713g

Are there any recommendations? Don't stand in the plane of rotation!

http://physics.info/sound/ The Physics Hypertextbook provides a wealth of additional information:

• The speed of sound in air is approximately 330 m/s (about 1,200 kph or 700 mph).
• The speed of sound in air is nearly the same for all frequencies and amplitudes.
• It increases with temperature. 1 ft diameter disc, radius 0.5 ft, .1524m 3000 rpm: ν = 3.14159*1ft*3000/60 = 157.080 ft/s , 47.878 m/s 4000 rpm: ν = 3.14159*1ft*4000/60 = 209.440 ft/s , 63.837 m/s (2726 G angular acceleration) 5000 rpm: ν = 3.14159*1ft*5000/60 = 261.799 ft/s , 79.797 m/s Even at 5000 rpm, this is far from trans-sonic, and v²/r is still only 137,078.5 ft/s² 41,782 m/s², (4260.6 G angular acceleration) It is possible to make transonic rotors - see this: http://www.ramgen.com/apps_ASCE_breakthrough.html I have queried the contact there about the possibility of utilizing exotic fuel-oxidant mixtures. I have a specific application in mind, but I also probably cannot afford one of their rotors (unless they want to set up shop at my buddy's farm).