240 volt vacuum motors - fan search.

[riga team]

[riga team]

[larrycavan]

[riga team]

TONY! I Has checked up blower, here results: on 2800 RPM about. I have received a minus of 0,02 kg/cm2 , on 5500 :-0,04 kg/cm2 and a stream on an output became warm : and it is bad. Now I reduce backlashes. On Monday the repeated test ANATOLIJ

[Tony]

Anatolij,

Those pressures sound far too low, and the temperature rise should be barely noticeable. I suspect your blower is operating well into the choke region and operating very inefficiently.

I would expect about 0.033 Kg/cm (13" water) at 2800 Rpm and about 0.132 Kg/cm (52" water) at 5500 Rpm with that particular rotor diameter.

Try restricting the inlet area of the blower with a smaller hole, and measure the developed pressure. My guess is that it will develop the expected pressures with probably up to about a 38mm diameter hole (1.5"). It may support an even larger hole than that, but at some point pressure and efficiency will fall as the blower becomes overloaded. It could be caused by restriction and pressure drop in the outlet scroll and duct, or by back flow inside the blower casing due to excessive clearance.

Try plotting flow and pressure with a series of different sized orifice holes, and see what that blower can do. High pressure blowers will never operate efficiently will full open flow, they all have some maximum flow capacity beyond which they just will not work. If that does not fix the low pressure, it must be an internal clearance problem.

When it is mounted in the flow bench it will always be working against some fixed test pressure, which acts as a flow restrictor. It will never have to operate at full open flow as it is probably trying to do now.

[ivanhoew]

right latest news ,forget the bit about 40uF per bhp ,looks like that a tad too much ,for a 4hp 3ph on a single ph suuply i need somewhere around 50 to 80 uf .so im off to the magic yard to find one ,oh ,its gotta be 250v ac or 360 v or more dc ,and not electrolytic ,so lets see what i can find .regards robert

[riga team]

TONY! I have made these changes to a blower and have received 0,11 KG/CM2 on 5000-5500 rpm . The stream has whistled: similar all will turn out, I for hermetic a cover.
Anatolij

[Tony]

Excellent result Anatoilj.

0.11 Kg/Cm is 43.3 inches of water (1.56 psi) which sounds about right for that rotor diameter and Rpm range. I doubt if you will be able to improve it much further than that. All you need to do now is measure developed pressure at various flows.

The pressure should stay fairly constant, and then begin to fall off fairly rapidly above some particular flow number. My guess would be full pressure up to around 150 CFM (255 cubic metres/hour). Flow will go higher than that, but not at full pressure.

[riga team]

TONY : I have picked up gears: GM (OPEL) ECOTECH 1.6 cm3 knees-shaft has 20 and other model 21 a tooth: VW on a cam - shaft 44 teeth: 44/20=2,2*2800=6160 RPM 44/21=2,095*2800=5866 RPM the STEP of the BELT APPROACHES. It already variations

[Tony]

That sounds pretty good Anatolij, those toothed automotive belts can handle a lot of Rpm and horsepower, but it may become a bit noisy at high belt speeds.

A few extra Rpm will make significantly more pressure, and flow will increase as well. But drive power increases dramatically too, so make sure you don't overload your motor. Doubling the Rpm would require at least eight times the drive horsepower.

[Tony]

Ivanhoew, here is a commercial Vortron high speed blower that appears to use a centrifugal supercharger type of compressor, and a very high ratio pulley drive system:

[Thomas Vaught]

Vortron is the industrial side of Vortech Engineering who makes the Racing superchargers.

The Vortron units are commercial grade units and are used (among other things) to clean ice from airplane wings without chemicals.

At some point I would like to have one of the set-ups.

Tom V.

[ivanhoew]

thanks tony , id seen that before ,looks like a simple turbo compressor with a belt drive , i got my 4hp motor on the juice today , just clicked and hummed to interuptor switch at first ,then blew the fuse in the plug ( yes i know it should be a dedicated feed ) so fixed that then tried a different capacitor 150uf instead of the 40 uf i think was dead ,it started !!! ran at low speed for a 20second period ,then ran up to proper 2800 i reckon ,very smooth too ...then tried it with the fan on it ,ran at low speed then trip went on the 16 amp feed,as expected really , i guess the torque needed to made the step to full rpm was a big current drain prob about 30 amps ? so off to get some big cable and breakers tomorrow,interesting how it runs at low speed then speeds up may be i need to check connections ,it should in theory be running a 40 uf ish cap when running ,and i thuoght it would start on that too ,but maybe it'll need the 150uf to start then a 40 uf for running ,this would be if the torque from the 40 uf is insufficient to get it up to speed .regards robert.

[Tony]

Robert, have you inquired about getting three phases connected to your home ?

[ivanhoew]

the situation with leccy supply is thus , i live on an ex government research establishment sold into the private sector in 95,the private ownwr of the site then sold off the 3 staff houses of which mine is one ,he didnt however ratify services at all ,which means i pay him for my supply ,and he pays the leecy company ,this is not good ,since i am total owner of my house , i did tie him into a legal contract ,and i do have a meter ,but to get three ph into the sit would add a whole new dimension of grief i feel ,frustrating really cos behind my house is a unit with 3 ph in it i think ,its all a bit deserted air base sort of feel ,regards robert.