Generator issue

[Al Smith]

I once started a 300 Hp ,480 volt synchronous motor with a lantern battery.---now the rest of the story .Those big old open frame motors were used because of the high power factor and could be over excited to act like a power factor correction capacitor .The exciter was screwed up on this one .It was an emergency situation ,after a shut down I found a faulty connection the exciter .

Most small generators are self excited alternators not so much different in design than an automobile alternator .The excitation is contained in main winding by the use of diodes and the residual magnetism in the armature .Some times they can be shaken loose by over riding the governors for a little bit .

I could babble on forever about this stuff but here's one .You can couple a 3 phase induction motor to a prime mover,start it up across the line on voltage,drive it to above "slip" frequency and it will in effect be an induction generator as long as it has a load on it .Google it if you want to .

I might add the above with a 3 phase motor is in essence exactly like a 3 phase rotary phase converter with the exception you turn one winding into a start circuit with a large capacitor .Once running you use a cap at around 7.5 microfarad per HP run cap,on 240 volt because the induced leg has in inductive lag which be lower than line voltage .With proper design these things are around 92 percent power factor .

 

[Crzybowhntr]

Here the OM and IPL for 46596. The wire diagram is in it.

Awesome! Thanks

 

[Crzybowhntr]

I once started a 300 Hp ,480 volt synchronous motor with a lantern battery.---now the rest of the story .Those big old open frame motors were used because of the high power factor and could be over excited to act like a power factor correction capacitor .The exciter was screwed up on this one .It was an emergency situation ,after a shut down I found a faulty connection the exciter .

Most small generators are self excited alternators not so much different in design than an automobile alternator .The excitation is contained in main winding by the use of diodes and the residual magnetism in the armature .Some times they can be shaken loose by over riding the governors for a little bit .

I could babble on forever about this stuff but here's one .You can couple a 3 phase induction motor to a prime mover,start it up across the line on voltage,drive it to above "slip" frequency and it will in effect be an induction generator as long as it has a load on it .Google it if you want to .

I might add the above with a 3 phase motor is in essence exactly like a 3 phase rotary phase converter with the exception you turn one winding into a start circuit with a large capacitor .Once running you use a cap at around 7.5 microfarad per HP run cap,on 240 volt because the induced leg has in inductive lag which be lower than line voltage .With proper design these things are around 92 percent power factor .

Al, you lost me at "I once started..." You sound like you definitely know what you are talking about!!

 

[Crzybowhntr]

took one apart a tsc so I could see where all the wires go.

 

[Al Smith]

Al, you lost me at "I once started..." You sound like you definitely know what you are talking about!!

Meaning on one occasion I had to jury rig this big old vertical motor/pump to get it started in a water treatment plant .With a synchronous motor it's started in rotation by shorting the armature winding,through a bank of big resisters often which act then like an iron armature induction motor .At approx 80 percent speed the armature is given a shot of DC current that it locks in at frequency speed .Very low speed motors and huge .This one was 6 feet across ,I've seen them over 15 feet and 2000 HP.

About the only places you even see this type is a really old installation .That particular one was installed in 1946,I wasn't even born until 1948.Fact I wasn't even a twinkle in the old mans eyes then .