Author Topic: `upgrade for the lister-petter (Read 5250 times)

pepa · « **on:** September 01, 2006, 06:19:53 PM »

i am in the process of adding a 5hp induction motor to to my lister to produce 60hz ac by driving the motor at a faster speed than it is listed at. i have read a lot of info. from the board and the web but could use some guieance if any of you have done this before. the specs on the motor are-emerson motor lr22132, hp special duty cont. (5hp), frame 56 type T, rot ccw, inc/class B, max/amb 40o/c kva code, volts 120/240, hz 60, rpm 3450, ph 1, amps 15.o/7.5, amps 5.98/49, sf 1.0, sfa, output 2.25 kw, i have three of these motors and would like to use one for this project if it will work. the picture below shows the motor mounted but i am waiting on a shaft extention that the Maker of toys has been kind enough to make for my toy. the flywheelpully is held in place by a clamp to allign the belt and bracket. thanks, pepa.

Bruce S · « **Reply #1 on:** September 01, 2006, 12:46:57 PM »

Hey Pepa;

If the arrow on the engine indicates pulley rotation direction , I think your about to have this thing going backwards from your info.

Also , way are you wanting to run it faster then it's needs? I'm thinking if you do this for a long period of time the bearings and internals are going to begin smoking , melting and all sorts of bad stuff.

Thoughts?

Bruce S

fungus · « **Reply #2 on:** September 01, 2006, 12:53:02 PM »

Induction motors have to be run at 10% over their rated speed to make power.

pepa · « **Reply #3 on:** September 01, 2006, 01:07:16 PM »

the rotation of the driven generator makes no difference except in the rotation of the fan. the rotor has strait fins on both ends and should cool in either direction at least that is what i hope. i will install a new pully on the induction that will give the proper rpm. the flywheelpully is ten inches and the one on the motor is only to align belt.pepa.

pepa · « **Reply #4 on:** September 01, 2006, 01:10:34 PM »

hi fungus, have you rigged one of these motor generators? thanks, pepa.

fungus · « **Reply #5 on:** September 01, 2006, 01:30:53 PM »

No, I havent I just read the board a lot:-)

Darren73 · « **Reply #6 on:** September 01, 2006, 05:48:51 PM »

going by the slip on the motor you should aim to run it at 3750 rpm

Regards

Darren

pepa · « **Reply #7 on:** September 01, 2006, 06:41:40 PM »

thanks darren, thats what the paper that i am following has for speed adjustment. i cannot find any information to tell me if i need the capacitors, start and run as came on the motor origanilly or not, do you have that information? the information only says to use run capacitors in paralleline with the power line leads. pepa.

thefinis · « **Reply #8 on:** September 01, 2006, 11:22:02 PM »

Are you going to excite it from an external source like the grid? That is what sets the fields and frequency for 60hz. You might could excite it from an inverter but if so I think that the inverter would have to be large enough to overpower the motor even at surge draw to keep the motor from trying to set the line hz. You shouldn't need the starter cap unless you plan to use it to start the pelter. The run cap may be needed depending on the voltage setting 120/240 but I am not sure about that. I think it is there for running on 120 if so it would still be needed if using it now to make 120. If you wire it for 240 I believe it bypasses the run cap and excites the fields from the line either way it should be okay to leave it in.

If you plan to run the motor off grid and let rpms determine hz then it is run with caps and you will need to add at least another run cap. When one is run this way I think that it is run at rated speed not plus slip. I am not at the computer with those links to look up how one was run off grid with caps or what size caps are needed.

Finis

pepa · « **Reply #9 on:** September 02, 2006, 07:00:04 AM »

thanks finis, the author of the paper that i have been working from, an easy to build and operate induction generator, does not mention any motors over 1hp so there is probly a difference between his directions and yours for this 5hp but he said that of all the motors he has worked with, that they all self started making electricty except one. he also stated that a motor with 3450 rpm rating should be driven at around 3700 rpm to produce 60hz, and in the event that it did not self start or was shut down under load that it could be started by applying 120 ac or 12v dc for a few seconds. i though that i had the info that i meeded for this project but will have to dig a little deeper. any helo will be welcome, pepa.

pepa · « **Reply #10 on:** September 02, 2006, 07:04:35 AM »

A plea for help from the electronic members. If I disable the centrifuged switch on the shaft and replace the start cap with a couple of run capacitors, will I be able to get any usable electricity if I tap into the caps from the start winding of the induction motor, drove as a generator, without letting windstuff's magic smoke out. The coil start wire is smaller than the run wire and I have not been able to find any information on this subject. It seems a shame to waist the winding by it being disconnected as the switch kicks in. My main problem with this machine is that I keep trying to find ways to get the mule to plow one more row before quitting time. Thanks, pepa

vawtman · « **Reply #11 on:** September 02, 2006, 08:38:28 AM »

Pepa this might be a crazy thought but what if you used a battery to replace the start cap?

Not sure what rpms the switch actually kicks out at.

Maybe use a diode to protect the battery?

If you get magic smoke you still have 2 more.

Just thought im throwin out there.

dinges · « **Reply #12 on:** September 02, 2006, 09:29:15 AM »

Stop throwing. Someone might follow your advice.

dinges · « **Reply #13 on:** September 02, 2006, 09:47:57 AM »

A DC voltage on a winding of an induction motor will cause the motor/genny to brake. If you don't believe me, take an induction motor, give it a good spin, and connect a 9V battery to the windings. It will brake.

If the DC current is high enough (low resistance winding, high capacity battery) the starting winding will burn out. That's why you use a 9V battery and not a 200Ah car battery.

A capacitor is not a battery, a battery is not a capacitor. Randomly replacing caps by batteries doesn't work. Randomly replacing batteries by caps doesn't work either; if you don't believe me, replace your car battery by a starter cap and see what happens. (answer: nothing)

How a diode would protect the battery is beyond me.

Like you, I can't answer Pepa's question. But hopefully I can stop him from following your advice/thought.

pepa · « **Reply #14 on:** September 02, 2006, 10:18:59 AM »

thanks peter, my knowledge of motors and eletronics of very limited and i do love to tinker, i would have tried it thanks again, pepa.

pepa · « **Reply #15 on:** September 02, 2006, 10:25:27 AM »

thanks vawtman, we will get through this project somehow, it is a learning experience and having fun to. if it doesn't work, no one will be hurt and i will go in another direction, pepa

vawtman · « **Reply #16 on:** September 02, 2006, 10:34:58 AM »

Peter all i was trying to do was EXCITE conversation on the matter and learn what not to do maybe.Remember were just dealing with the start winding here and the switch.

The only thing the 3rd engineer agrees upon is this is fun.

vawtman · « **Reply #17 on:** September 02, 2006, 01:06:35 PM »

Pepa heres another idea.

Maybe use a nc relay instead of the diode.

Tied to the switch so that when the rpms are right and things get started the battery would be free.

Here i go again.

Ive been a member for awhile and while postings want to go this route havnt read success stories yet.

V.....The 3rd;<)

pepa · « **Reply #18 on:** September 02, 2006, 01:58:12 PM »

hi vawdman, this whole project is what, i hope to be, a working unit that will include several functions at one rate of fuel use. i have never worked with a diesel before, i have never used a induction motor as a generator. i do have a man who runs a small junk yard and alternator shop close by, teaching me the secrets of auto alternators. and i am taking a course in electronics as well but at 69 in three months and classed by the government ss as totally disabled, i dont know why i do it, except for something to do. i want to push this diesel engine as hard as i can to produce as much energy as i can and hope someone some where can benefit from the mistakes and achivements that i make with it. this board and this hobby has given me some very injoyable hours, as i have to set here for about two hrs, three times a day on the machines. in between times i go to the shop and work on a verity of projects and ideas that came from the different web sites and one of my own every now and then. you like to experiment and wont let others with less enthusium slow you down, i like that. keep them spinning, pepa

Flux · « **Reply #19 on:** September 02, 2006, 02:23:24 PM »

Single phase motors don't make good induction generators especially when you try to run them self excited.

You would probably do much better with a 3 phase motor even if you only need single phase.

As you have got it set up you might as well try it, it should work up to a point.

I take it that you are trying to self excite it using capacitors rather than trying to grid connect it.

You will most likely not be able to use the start winding unless you are very careful about capacitor values you connect across it.( you must disable the start switch if you want to try the start winding.

For a start I would try to get the run winding to self excite. Keep increasing capacitance until it builds up. You can run at nameplate speed or a bit more. Unless you have any frequency sensitive loads you may need to run a bit below synchronus speed to have a good compromise between volts and frequency. Nameplate speed will be a good starting point.

The more capacitance you add the higher the voltage and the worse the low load efficiency but the better it will maintain load. It should be ok for non critical loads but regulation will be poor and motor starting ability will be extremely limited.

If you can't get satisfactory results with the run winding alone you can add some capacitance to the start winding but check that you dont go too far , it will be easy to fry the start winding if it is intended for start only. If capacitor start and run then it will have a better chance, use the run capacitor but don't use the electrolytic start capacitor.

Induction motors are more suited to line operation, in which case they do have to run above synchronus speed and the poor regulation is no longer an issue.

They really are pretty poor stand alone alternators and are only suitable for loads such as portable tools and fixed load lighting. I wouldn't use them to drive anything critical unless it is a small percentage of a fixed load, in which case the voltage regulation may be good enough.

Good luck.

pepa · « **Reply #20 on:** September 02, 2006, 04:38:45 PM »

thanks for the information flux, and keeping me on the right track. i have learned a lot just from your answers to members questions. pepa

zubbly · « **Reply #21 on:** September 02, 2006, 05:32:10 PM »

hello Pepa,

if you have a black plastic capacitor and a metal cased capacitor, your motor is capacitor start and capacitor run.

#1 remove the black plastic capacitor and connect the 2 wires together you removed from it. leave the metal cased capacitor in place.

#2 connect your motor low or high voltage as per name plate connection diagram.

#3 you will need some more motor run capacitors (they are usually marked 370vac and come in approx 5MFD to 60 MFD sizes. i expect you will need at least an additional total of 60 MFD or more.

#4 start off with approx 40 MFD of capacitor connected in paralell to where you would have attached your power lines.

#5 drive the motor up to approx 3700-3900 rpm. at this point you will have to check the 2 lines with an ac volt meter to see what the voltage is. keep adding more run capacitors all connected in paralell with the 2 lines until you achieve the desired voltage you connected the motor for to start with.

#6 you may find you will have to set your voltage a little higher without load on it to compensate for when it is under load. once you have it putting out respectable voltage, apply load and take a volt reading again. you may find that you may still have to add additional caps to bump the voltage back up a little.

i have never done this before, but in theory it works and many have done it with good success.

let us know how it works out!

zubbly

wdyasq · « **Reply #22 on:** September 02, 2006, 05:58:12 PM »

Pepa,

You have gotten some good advice and some advice that will cause you greif. Please choose carefully.

Small diesels are happy running in the 25-75% power range. At that power setting it will use about gallon of fuel for every 20 hp/hr it runs. The point of pushing the engine too hard is when the exhaust goes from pretty clean to smoke. It can be checked with an exhaust gas pyrometer. Your 6HP engine should be happy if it is using less than a quart an hour.

Good luck,

Ron

thefinis · « **Reply #23 on:** September 02, 2006, 06:08:45 PM »

One quick question how do you plan to load it? It will work best with a constant load near max.

http://users.aber.ac.uk/iri/WIND/TECH/MISC/MotorsAsGenerators.html

Fair detail at the end on using and choosing caps

http://www.qsl.net/ns8o/Induction_Generator.html

Probably the file you have

http://sleekfreak.ath.cx:81/3wdev/CD3WD/APPRTECH/SK24VE/B1709_6.HTM

may be too detailed

I would try and talk to Nando as this is one of the schemes that is sometimes used with hydro and he will know if anyone does how to make it work best. I am not a fan of induction generators for off grid stand alone. I think they are great for grid tied.

You have gotten some really good answers especially as I am not sure anyone here as run one as stand alone before.

Finis

Kilroy2k1 · « **Reply #24 on:** September 02, 2006, 07:12:50 PM »

This method does work well on even single phase motors but... (always a catch isnt there) the 3450 types, well they just plane suck. If it does manage to self excite you will find you need to keep a tight reign on driven rpm and load and you have to severly derate them or you will let out lots of the magic smoke.

In the industry we call 5hp 3450 motors fake fives because the manufacturers rate them by rotor lock amps rather then true running load amps, in reality they're barely 3hp and closer to 2.5hp at anything over 50% duty rating.

Tom S.

pepa · « **Reply #25 on:** September 02, 2006, 08:26:28 PM »

thanks good people, i have about fifteen motors that i have collected in my good pile and the three air compressor motors are the largest of the bunch and all are single phase. the idea of adding the indunction came when i read a article from www,qsl.net/ns8o/induction_generator.html the man made it sound easy and was very proud of his work. i have installed the motor so that it can be removed simply by pilling a door butt pin and the belt. Ron thanks for the info on the diesel, i do not want to break it and will back off on the overloading. Zubbly i have admired your work and have read every thing that you have posted. i would like to do a conversion one day. i will follow your instructions and try some test with this motor. thanks Kilroy you sound like you know your way around motors and i will try to find a three phase or i will abandion this project and go to something else. thanks again all, pepa

Flux · « **Reply #26 on:** September 03, 2006, 01:21:24 AM »

I am not familiar with N American motors but after reading the name plate data I suspect Tom S is right, when it mentions special duty and 2.2kW. It looks very small for a true 5hp single phase motor. They don't exist here except as imports. True 5hp single phase are special order and cost the earth from our manufacturers.

Just another comment that I didn't make clear in the last post about the run capacitor. For a motor it is connected in series with the start winding and the line.

For working as an alternator I don't think this is a wise place to put it. If you need to use the start winding at all I would put a capacitor directly across this winding and not connect it to the load winding in any way. Don't try to pull any power from the start winding, just use it to aid the excitation. If you leave the original series connection it may still be adding lagging current.

pepa · « **Reply #27 on:** September 03, 2006, 09:12:47 AM »

thanks again flux, after all of the good info. i received from this post i now know that this motor is not good enough for what i wanted to do. i also want to apoligize to Bruce S for my misinformed comment about this motor being able to run in both directions with no ill effects. after more research it seems that driving the motor in a directon different from the name plate direction will cause the output to be less than it should be, do to the maginification of the rotor. i will hold off on this experiment until i can locate a suiteable three phase motor. thanks again everyone, pepa

News:

Author Topic: `upgrade for the lister-petter (Read 5250 times)