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RE: 3 phase converting

Original poster: "Gary Weaver" <gary350@xxxxxxxxxxxxx>

> [Original Message] > From: Tesla list <tesla@xxxxxxxxxx> > To: <tesla@xxxxxxxxxx> > Date: 1/18/2005 2:08:54 PM > Subject: RE: 3 phase converting > > Original poster: "Matthew Carlson" <mjc8804@xxxxxxx> > > That is some great info. We don't much use 3 phase in residential here, > but it seems to make alot of sense.

I have a work shop behind my house.  There is no 3 phase in a residential
area.   I have a Bridgeport Milling machine, Surface Grinder, Lathe, Air
Compressor, vaccuum pump, Hydraulic Press, Tubing bender, band saw, cut off
saw, table saw, wood planer, Welder, several other 3 phase items all in my
work shop behind the house.  I use to run everything on a static 3 ph
comverter which makes all the equipment run at 2/3 power.  Everything ran
fine except for the surface grinder at 2/3 power.   For awhole I run a
rotor motor but the rotor motor running all day long vibrating and buzzing
drove me nuts.   The rotor motor used a bunch of unnecessary electricity
and runs up my electric bill so I got rid of the rotor.   Now if I need
full power on one of the machines I turn on another motor in the circuit
and use it as the rotor.    3 phase equipment is dirt cheap because no one
wants it at home because they don't know how to make 3ph equipment run on
single phase.

I have a friend that has a 10 hp saw mill.  We connected two 5 hp motors in
parallel.  Sence both motors will run at full power we decided to put a
pully on both motors and run a V belt from each motor to the main drive
shaft.  It works great.  He gets 10 hp using two 5 hp motors.

Gary Weaver

> > > > >>> "Tesla list" <tesla@xxxxxxxxxx> 1/18/05 8:35:24 AM >>> > Original poster: "Gary Weaver" <gary350@xxxxxxxxxxxxx> > > It is not necessary to build a 3 phase converter that is complicated. > > Connect the 2 wires from the 240 volt ac directly to the 3 ph motor > through > a double pole switch. L1 and L2. > > Connect a run capacitor between the unused wire of the 3 ph motor to > one of > the other motor wires. L3 to L2. > > Connect a start capacitor in parallel with the run capacitor using a > momentary ON timer relay set to 1 second. To make it very simple the > relay > can be replaced with a normally open push button switch. Push and hold > the > button to start. When the motor comes up to full speed release the > button. > > The RUN cap should be 30 mfd per horse power. A 5 hp motor needs 30 x > 5 or > 150 mfd. Gray color oil filled cap. > > The Start cap should be 60 mfd per horse power. A 5 hp motor needs 60 > x 5 > or 300 mfd. Black color plastic cap. > > Then the power is turned on the 2 caps are in the circuit. The caps > provide a signal that fools the motor into thinking it is running on 3 > phase so the motor starts. Once the motor comes up to full speed the > timer > drops out the start cap. The run cap stays in the circuit all the > time. > The 3ph motor will run on 2 winding. With only 2 windings producing > power > the motor will run at 2/3 power. A 3 hp motor will produce 2 hp. > > The unused winding of the motor pics up the magnetic field and acts as > a > generator. If you connect another motor in parallel the 2 motors > gererate > power to each other and both motors will run at full power. One motor > is > NOT USED and is called the ROTOR motor. It the rotor motor is a 5 hp > motor > it will run 3 other motors of equal HP or a total of about 15 hp so be > sure > to use wire large enough in the circuit to handle the current. The 5 > hp > rotor motor will also power any combination of motors up to about 15 > hp. > You can run 15 different motors all 1 hp each on a 5 hp rotor. You can > run > 7 motors all 2 hp each. You can run one 5 hp, one 3 hp, one 2 hp, one > 4 hp > motors. You can run ten 1 hp motors and one 2 hp and one 3 hp. Any > combination up to 3 times the size of the rotor motor. > > If you have a work shop with a milling machine, lathe, grinder, air > compressor, etc. and the largest motor in your shop is a 5 hp then > build a > 5 hp motor starter with 2 caps. Connect all the machines in parallel > in > the same circuit. The 2 caps will start and run any piece of equipment > you > have in your shop and make it run at 2/3 power. Suppose you are using > the > surface grinder and 2/3 power is not enough power then turn on the > milling > machine and let the motor run but do not use the milling machine. > The > milling machine motor will act as the rotor in the circuit causing the > surface grinder to run at full power. Any motor in your shop can be > turned on and used as the rotor. If you need a rotor motor running all > the > time then buy a damaged 3 phase motor from a motor repair shop. 3 > phase > motors sell as mixed metal at the scrap yard for 2 cents a lbs. A 5 > hp > motor new aluminum style will weigh about 50 lbs. Offer them $5.00 > and > they will probably sell it. Some shops pull the copper wire from old > motors it gets them a better price on copper but they have to pay > workers > to do this so there is not much advantage to it unless they have > workers > with nothing to do and they have to pay them anyway. A damaged motor > with > a bent shaft, damage keyway, broken mount will work fine for a rotor. > > Gary Weaver > > > > [Original Message] > > From: Tesla list <tesla@xxxxxxxxxx> > > To: <tesla@xxxxxxxxxx> > > Date: 1/17/2005 6:48:39 PM > > Subject: 3 phase converting > > > > Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx> > > > > Ran across the following, which may be of interest: > > http://www.airraidsirens.com/proj_3phase.html > > >