Author Topic: External regulator V Governor as regulator  (Read 10929 times)

GerryH

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Re: External regulator V Governor as regulator
« Reply #15 on: December 29, 2005, 04:23:21 PM »
Hi WW1Props,
Yes Trygzy is technically right. but voltage is also a product of rpm and the exciter wattage. you can increase voltage by increased rpm. You cannot generate 3 phase this way to my knowledge. You can get single phase and have it cycle in step with the line power providing excitation, and when the line power quits you will loose excitation and the gen will not be backfeeding your power company. Then, of course you will want to self excite it to see you thru the blackout and switch back to line excitation when the power comes back. Ooops, switched it early by mistake, did we?
My personal opinion is that it is not in the best interests of the lineman working on the line to be depending on your homegrown protection to not power up the line he thinks is dead. Unless the profit margin is real wild I would not try to sell or reverse the power meter unless I had wind or water power. The source of these may be free, but even then, the mainanence surel isn't.

Gerry

WWIProps

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Re: External regulator V Governor as regulator
« Reply #16 on: December 30, 2005, 02:48:06 AM »
Thanks Gerry,

My system is approved by the local utility.  No capacitors allowed or other excitation other than grid power.  The magnetic contactor prevents the backfeeding should the power fail.  The single phase motor works.  Unfortuantely I haven't found many single phase induction motors over 5hp so am interested in how to rig up a three phase unit to do what I am doing today.

I still have my old generator for off grid operation when the utility fails but am considering a really small unit for excitation.  I am still uncertain of how large a unit I need to meet the excitation requirements of my listeroid 6/1 3.7 kw.

I run with WVO on a combined heat and power system.  It is paying for itself quite nicely.  Maintenance may be an issue in the future but it keeps me out of trouble and my wife likes it because parts of the house are hotter than we would have kept them without this system.  Besides, its fun!

Thanks,
Scott

Doug

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Re: External regulator V Governor as regulator
« Reply #17 on: January 08, 2006, 03:00:35 AM »
Generating power with an Induction motor is called "Asyncronous generation".

Short list of comments based on what I've read:
You can use a 208 motor to generate single phase but the losses are higher than you would get with a capacitor run single phase and even that isn't as effcicient as something like an ST head (the brush kind are the only way to go in my opinion).

You can generate stand alone power with a Capacitor bank to provide the reactive power for feild excitation but because rotor currents are slip induced you have to drive the motor above its sync speed and monitor you frequency and voltage. This can be a real problem if you have a load change because now you have to change your motor speed to hold 60hz and adjust your capacitance to hold your voltage steady.

And you can even generate 3 phase if you like this way. In a grid connected system using two legs a three phase motor the third unused leg is actualy generating a third phase by induction you can use to start and run other three phase motors. Be warned the third leg of your new three phase system will be a little on the weak side don't expect it to start heavy loads like a 10hp compressor or run a welder.

Doug
Last but not least charged motor Capacitors can hold enough power to cause harm. I used to have a boss with whom I share a mutual hate. I used to charge caps on my test bench (to about 60 v) and leave them about the shop or stock room, and then ask him if he seen one because I need one and can't find any.

Heh heh heh!!!!

Bansonyankee

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Re: External regulator V Governor as regulator
« Reply #18 on: January 15, 2006, 02:30:47 AM »
With respect to speed governors, on my utility-parallel setup, it's not an issue since the utility controls the frequency.  All the governor does at that point is maintain the power output at the set point.  If the utility disconnects, then the speed governor "catches" the engine as it speeds up after being suddenly unloaded.

For the grid-independent folks, the mechanical governor on the Listeroids does an amazingly good job of speed regulation, considering how crude it is.  If someone needs dead-accurate frequency control, we can fix them up with an electronic governor.  These are made by Woodward, Governors America, and Synchro-Start.  There used to be another company, Barber-Colman, but they were bought by Woodward.  The system has three components, a speed sensor, throttle servo ("actuator") and the governor ("brain").  It'd require mounting a ring gear somewhere so there are gear teeth for the magnetic speed pickup to sense, but it could give very accurate speed control from zero to full load ("isochronous governing").  The cost for the whole setup would approach $1,000. 

Frankly, I doubt anyone on this forum really needs that level of accuracy on their frequency control.  Just don't run your alarm clock on the Listeroid. 

J.S.
Highland Power

Procrustes

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Re: External regulator V Governor as regulator
« Reply #19 on: January 15, 2006, 08:24:51 AM »
Thanks Gerry,

My system is approved by the local utility.  No capacitors allowed or other excitation other than grid power.  The magnetic contactor prevents the backfeeding should the power fail.  The single phase motor works.  Unfortuantely I haven't found many single phase induction motors over 5hp so am interested in how to rig up a three phase unit to do what I am doing today.

I still have my old generator for off grid operation when the utility fails but am considering a really small unit for excitation.  I am still uncertain of how large a unit I need to meet the excitation requirements of my listeroid 6/1 3.7 kw.

I run with WVO on a combined heat and power system.  It is paying for itself quite nicely.  Maintenance may be an issue in the future but it keeps me out of trouble and my wife likes it because parts of the house are hotter than we would have kept them without this system.  Besides, its fun!

Thanks,
Scott

Whoops, I didn't see this post until just now.  Thanks for answering these questions a second time.  I'm impressed with your setup!

Procrustes

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Re: External regulator V Governor as regulator
« Reply #20 on: January 15, 2006, 08:32:32 AM »
With respect to speed governors, on my utility-parallel setup, it's not an issue since the utility controls the frequency.  All the governor does at that point is maintain the power output at the set point.  If the utility disconnects, then the speed governor "catches" the engine as it speeds up after being suddenly unloaded.

For the grid-independent folks, the mechanical governor on the Listeroids does an amazingly good job of speed regulation, considering how crude it is.  If someone needs dead-accurate frequency control, we can fix them up with an electronic governor.  These are made by Woodward, Governors America, and Synchro-Start.  There used to be another company, Barber-Colman, but they were bought by Woodward.  The system has three components, a speed sensor, throttle servo ("actuator") and the governor ("brain").  It'd require mounting a ring gear somewhere so there are gear teeth for the magnetic speed pickup to sense, but it could give very accurate speed control from zero to full load ("isochronous governing").  The cost for the whole setup would approach $1,000. 

Frankly, I doubt anyone on this forum really needs that level of accuracy on their frequency control.  Just don't run your alarm clock on the Listeroid. 

J.S.
Highland Power

Here http://surplusman.com/P_GAC.php?menuid=20#Actuators is a page with some intriguing gear along these lines.

Incidentally, I'm amazed that you are setting up grid-tie in Massachusetts.  My time there was a prolonged cornholing: fines for not clearing the ice from the sidewalk in front of your house, getting your car towed for inscrutable reasons, getting permission to paint your front door, the DOL giving handicapped parking stickers to their buddies.  But there's much that I miss about it too.