240 volt vacuum motors - fan search.

[Tony]

[quote="ivanhoew"][color=#000000]well thats very kind of you to try tony ,i was looking at those variable frequency drives ,that appear to offer as you say a change to dc then back to a 3 ph output with a pad on the front with the up and down arrows for rpm ,but it woulds appear that they only go up to about 2hp for single phase .at least thats what have found so far ,my next thought is an inverter as one would use for chANGING 1 PH TO 3 PH ,with out a speed control just a throttle valve on the inlet adjustable for area like a big butterfly valve,from what iv read this would also mean that my power consumption would drop at the lower flows so costing me less in my power bill !,i have found a 3hp single ph motor new for

[Tony]

[Tony]

[ivanhoew]

[color=#000000]the story so far .i have found a vfd that will drive a 5hp 3ph motor from domestic single ph ,it was

[riga team]

Tony, Having washed blower I have found out very much greater backlashes between a rotor and the case: fig. 1-2-3-6a . I wish to change it: fig. 6b . To leave a crack of 1 mm from a cover. And to fill sector fig. 4-5: too 1 mm. So I did at two steps of the motor from a vacuum cleaner where have received an increase of vacuum of 0,03-0,04 kg (instead of-0,17 became-0,20). p/s -0,20 the kg gave motors from kacher vacuum motors and others ANAtolij

[Tony]

Anatolij,

That clearance in "Blow 1" seems to be a design feature of every centrifugal blower I have ever seen. Some air is always allowed to flow completely around the housing past the outlet. I am not sure why, but it must offer some sort of advantage, so don't worry about it.

The clearance to the front cover "Blow 2 & 3" is going to allow some air to travel from the outlet back to the inlet, and reduce the available pressure and flow. It should not be too difficult to fit something inside the cover to fill that space. The ideal solution would be to turn up a whole new aluminium front cover on a lathe. Another way might be to make a completely new cover from fiberglass.

Make the cover so it comes as close to the rotor blades as possible, but do not fill up the space beyond the tips of the rotor. Keep the expanding outlet duct part of the housing as large a flow area as possible.

It may even be possible to build a second outlet port in the front cover which may increase the flow capacity. The existing outlet looks very restrictive compared to the rotor and the inlet. Quite a few things could be tried without making any irreversible modifications to what you already have.

To develop more pressure is easy enough, it just requires higher drive Rpm. Flow will increase as well.

[Tony]

Ivanhoew,

I purchased a brand new Chinese VFD simply because it came with a guarantee and the operating manual. The problem with e-bay and machinery auctions is that getting information or any repairs done may be extremely difficult.

Modern VFDs are absolutely packed with the most amazing range of useful features, but initially programming the thing can be a real ordeal. It is like programming an unfamiliar video recorder. There will be an absolute maze of keystrokes required to work your way around the various available features and functions. Having the correct operators manual is an absolute necessity.

Like most modern electronic devices, the market is extremely competitive, and prices are falling. I paid $1,200 Aussie dollars for this 10 Hp drive (498 English pounds) about two years ago. It is a lot of money, but I have never regretted it.

This particular drive can be speed controlled by up down arrows, by entering the desired speed numerically via the keypad, from an external dc input voltage (or control knob), or from the serial port of a computer. It also has a controlled ramp up of speed, so there is no massive starting surge, and I can set the maximum output frequency at anything up to 400 Hz. It is a marvelous way to control airflow, and at low Rpm settings the flow bench runs almost silently.

[riga team]

TONY Where preference:
10 hp 3 phases or 10 hp 31 amp collector the motor ?ANATOLIJ

[Tony]

[riga team]

[color=#000000][quote="ivanhoew"]the story so far .i have found a vfd that will drive a 5hp 3ph motor from domestic single ph ,it was

[ivanhoew]

thank you very much anatolij,i am investigating a book i bought about motors in the workshop ,it seems to be saying to me that with a capacitor in the right place i can run my 3 ph 5hp motor on single ph with only a small drop in power!! so this sounds v exciting.. tony your absolutely right , the vfd would have to be all up and with all its paperwork to be any use .i am off to canada in may ,so may take a trip to the border if i have the money ,and get that indiana one for the 270 .but if i can plug this motor in ,it would be highly exciting ,,,and just a bit scary .regards robert.:p

[Tony]

Just make absolutely sure that an American sourced drive is not limited to running off the American 120v supply system, with an American 120v three phase motor.

If you plan to run it in the UK, 50Hz/60Hz makes no difference, but the rather large voltage difference sure might be a very big problem.

You will need a lot more than just a capacitor to run a three phase motor off single phase, it just is not going to work.

In Australia we have 240 volts between each phase and neutral, and 415 volts between each of the three individual phases (ignoring the neutral). I believe the UK and Europe is similar, except it is 230/400 volts instead of 240/415 ?

Anyhow, if you only have single phase coming into your home, all you get is neutral, and one 230 volt phase. The motor requires three phases of around 400 volts between each. No neutral is used with these motors, only three supply wires. So you are just not going to have enough voltage to run even one of the three motor windings.

Honestly, unless you are renting, enquire about getting all three phases hooked up to your home. They are probably right there out in the street. It cost me nothing to get my electricity meter upgraded and all three phases connected to my power board. From there, I only had to get a qualified electrician to run a three phase feed from the power board to my garage/workshop. That did cost me, but it was peanuts.

[larrycavan]

[Tony]

It is because of Historical precedent. Like all the different gauges of railway lines around the world, different countries started off completely independently.

There even used to be large public dc power distribution systems in the very early days of new fangled electric power, but the many advantages of ac quickly eliminated all of those.

Once a public electricity supply system begins, it just continues to grow. The cost of scrapping all existing equipment and starting out again totally from scratch would be astronomical, with little real benefit in doing so.

The Americans basically run 120/230 60Hz, Europe is mostly 230/400 50 Hz, not sure abut Russia, India or China, but Japan is a really odd 100/175 60Hz.

Buying motors and VSDs on e-bay may be fun, but make damned sure whatever it is, can be used in your own location, or that real bargain may turn out not to be.

Exactly the same problem occurs with radio and television receivers. Different wavebands and different numbers of scanning lines and systems of modulation.

Your computer monitor is totally different to any normal TV set. And even in our cars we drive on different sides of the road. Oh what a mess !!!

[riga team]