Hi Nando, Could you expound a bit on the "(synchronous current detection)" that you mention. I use a clamp on meter as an amperage detector. As I change nozzle configuration on a pelton I can see my Kw's.
David ----- Original Message ----- From: "Nando" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Friday, May 06, 2005 5:23 AM Subject: Re: [microhydro] Digest Number 1153 > Perran: > > The induction motor (Generator) GRID connected, follows the GRID frequency > and the RPM of the GEN, in this case, is going to be the RPM defined by > the > number of poles and the GRID frequency PLUS twice the SLIP Value. > To detect this you may have an RPM detector to make sure that the GEN does > not run as a motor, which happens if the hydro pressure lowers. > Also, techniques like reading the current into the grid with the voltage > as > a reference to detect the current direction -- this is faster and more > accurate.(synchronous current detection). > > Frequency will not move from the GRID frequency-- it can not move ( > vary) > because the motor bias is set by the GRID. > > If the generator has excessive applied torque ( by the Turbine), one may > have issues like heavy currents and (PF) Power Factor. > > And for those interested, one may have two hydros operating in parallel, > in > where one is a master (GRID) and the other is the slave ( in this case an > induction motor) which should be capable of producing not more that about > 50 > % of the master. > > Regards > > Nando > > > > ----- Original Message ----- > From: "H2MJD" <[EMAIL PROTECTED]> > To: <[email protected]> > Sent: Thursday, May 05, 2005 8:48 PM > Subject: Re: [microhydro] Digest Number 1153 > > >> >> Can someone tell me how you can provide this 'utility required' >> protection >> with a directly connected induction motor. My understanding is that power > will >> flow into or out of the grid in a seemless manner depending only on the > speed >> of the motor/generator shaft and the torque applied. Am I right ?? >> >> Perran Newman >> >> >> >> Perran, >> You are right. When wiring in the motor/generator typically a magnetic > contactor (motor starter) is used to apply power to the unit. The > Over/under > voltage and over/under freq relays monitor the voltage and frequency of > the > utility power. If the voltage or freq move outside the utility perscribed > limits(and this will only happen if the utility is experiencing a problem) > these relays will remove power from the magnetic contactor's coil and the > motor/gen will then be isolated from the utility grid thereby providing > safety to all.......i hope this helps.......mark >> >> >> >> >> >> >> [Non-text portions of this message have been removed] >> >> >> >> >> >> >> Does your company feature in the microhydro business directory at > http://microhydropower.net/directory ? If not, please register free of > charge and be exposed to the microhydro community world wide! >> >> NOTE: The advertisements in this email are added by Yahoogroups who > provides us with free email group services. The microhydro-group does not > endorse products or support the advertisements in any way. >> >> More information on micro hydropower at http://microhydropower.net >> >> To unsubscribe: send empty message to > [EMAIL PROTECTED] >> Yahoo! Groups Links >> >> >> >> >> >> > > > > > > > Does your company feature in the microhydro business directory at > http://microhydropower.net/directory ? If not, please register free of > charge and be exposed to the microhydro community world wide! > > NOTE: The advertisements in this email are added by Yahoogroups who > provides us with free email group services. The microhydro-group does not > endorse products or support the advertisements in any way. > > More information on micro hydropower at http://microhydropower.net > > To unsubscribe: send empty message to > [EMAIL PROTECTED] > Yahoo! Groups Links > > > > > > > > ------------------------ Yahoo! Groups Sponsor --------------------~--> Has someone you know been affected by illness or disease? Network for Good is THE place to support health awareness efforts! http://us.click.yahoo.com/RzSHvD/UOnJAA/79vVAA/FGYolB/TM --------------------------------------------------------------------~-> Does your company feature in the microhydro business directory at http://microhydropower.net/directory ? If not, please register free of charge and be exposed to the microhydro community world wide! NOTE: The advertisements in this email are added by Yahoogroups who provides us with free email group services. The microhydro-group does not endorse products or support the advertisements in any way. More information on micro hydropower at http://microhydropower.net To unsubscribe: send empty message to [EMAIL PROTECTED] Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/microhydro/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
