Trevor - I'm looking for an affordable solution to a load problem. I have an AC Grunert AC450 compressor with a both start and run capacitors running the fridge and freezer on my boat. It draws 7-9 amps when running and 30-35 for half-a-second at start up. My boat does not have an installed generator and I spend a significant amount of time away from shore power. I use a Honda 2kw generator for power on the hook. It can produce 25 amps for 5 seconds and can run forever at 15 amps. 20% of the time it starts the fridge. 80% it either takes multiple tries or it won't start it at all. I don't want to drop $5k on a new DC cooling system b/c the Grunert works flawlessly. I also don't want to drop the $$ it would take to install an diesel genset. Is there any way to attenuate that 30+ amp startup load so I can run this system off my 2kw? I tried installing a hard-start kit, which is a capacitor that hooks into the existing run capacitor, but it made no difference. I've read about using an "inductor" or "filter choke" to attenuate the start-up load but I can't find enough info to know if this is an option. Any input would be appreciated. Regards, Jim
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Isolation
Have you tried shutting down all AC equipment except the frige? sounds like thats whats happening if some time it works and some time it won't, You might want to try a 3k gen set maybe you can borrow a friends and try it out b4 buying Fair winds RAD ~ /) ~
Have you tried shutting down all AC equipment except the frige? sounds like thats whats happening if some time it works and some time it won't, You might want to try a 3k gen set maybe you can borrow a friends and try it out b4 buying Fair winds RAD ~ /) ~
Genset limitations
Hi Jim - You have described the challenge of AC gensets on boats. High inrush current require gensets which are 6-8 times the operating load requirements to meet the surge load on start-up. I do not know of a solution you have not tried but several vendors are trying; see info on Glacier Bay's OSSA Powerlite solutions. Help might be on the way... Trevor
Hi Jim - You have described the challenge of AC gensets on boats. High inrush current require gensets which are 6-8 times the operating load requirements to meet the surge load on start-up. I do not know of a solution you have not tried but several vendors are trying; see info on Glacier Bay's OSSA Powerlite solutions. Help might be on the way... Trevor
Hard Start Capacitors
‘Soft Start’ ~or~ ‘Hard Start’ Capacitors: I don’t normally recommend aftermarket Hard-Start capacitors, as they represent a band-aid approach to solving the problems associated with undersized generators, inverters, or wiring, or “sticky” compressors. A “hard start” system consists of a start capacitor and relay, wired in parallel across the “run” capacitor (One wire goes to the RUN side of your compressor run capacitor and the other wire goes to the START side of the compressor Run capacitor.). When the compressor tries to start, the start capacitor provides a voltage boost to the start winding of the motor, andhelps the motor rotor to turn. At some point, when the capacitor is released from the start winding, the motor continues to run Failure of the start relay to cut the start capacitor out of the circuit, or improperly sized capacitors, could burn out the start windings, or overheat the capacitor (a severe fire hazard). Hard start components, for a particular compressor, must be selected from the manufacturer’s information, as each compressor motor manufacturer specifies the correct start capacitor and potential relay characteristics. These capacitors store a high amount of power which will give a nasty shock. See also “KickStart”: http://www.kickstartoem.com/faqs/contractors.html
‘Soft Start’ ~or~ ‘Hard Start’ Capacitors: I don’t normally recommend aftermarket Hard-Start capacitors, as they represent a band-aid approach to solving the problems associated with undersized generators, inverters, or wiring, or “sticky” compressors. A “hard start” system consists of a start capacitor and relay, wired in parallel across the “run” capacitor (One wire goes to the RUN side of your compressor run capacitor and the other wire goes to the START side of the compressor Run capacitor.). When the compressor tries to start, the start capacitor provides a voltage boost to the start winding of the motor, andhelps the motor rotor to turn. At some point, when the capacitor is released from the start winding, the motor continues to run Failure of the start relay to cut the start capacitor out of the circuit, or improperly sized capacitors, could burn out the start windings, or overheat the capacitor (a severe fire hazard). Hard start components, for a particular compressor, must be selected from the manufacturer’s information, as each compressor motor manufacturer specifies the correct start capacitor and potential relay characteristics. These capacitors store a high amount of power which will give a nasty shock. See also “KickStart”: http://www.kickstartoem.com/faqs/contractors.html
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