Frequency problem

[KratzDavid]

New to the forum as of last night. Just installed a 5244 16 KW Genset.

Everything seemed great. It fired right up manual and auto. Transfers nice and smooth. 4 ton AC on line, no problem. Checked voltages with 125 v on each legs and 250 on both under load -122 v & 245 V no load.

My HVAC buddy came over tonight to check gas presures. The tag on the Generator said they should be between 5 and 7. The presure read 5.2 with no load and 5.2 under heavy load. Rock solid. I'm thinking this is way to easy.

Now the problem. I checked line frequency from the utility company and it was rock steady at 60 HZ. I checked it with the generator and it was a very unstable 178 hz. The meter was a very unstable up and down. The same results loaded or unloaded. I can't understand. Using a cheap Sears DVM that reads frequency. Thought it might be the meter, but why is the line steady.

Note: Using a cheap spark plug wire speed sensor, reads 3450 RPM instead of the stated 3600 RPM.

I'm at a loss...Help.

Thanks in advance,

DJ Kratoska

[SkipD]

David, part of the problem could easily be the cheap meter giving you incorrect frequency readings. The output of my 5416 generator is definitely not a perfectly smooth sine wave - probably due to the electronic voltage control circuits, just like in my portable generator (a top of the line Generac 6.5KW from about ten years ago).

It would not surprise me that the generator runs at about 58Hz at no load. The generator would be running at 3480 RPM if it were at precisely 58Hz. I'll let the generator experts add more, though, as I don't know anything about your specific generator. My 5416 (new less than a month ago) ran at 58Hz ±.2Hz until the dealer found out about a DIP switch setting change that makes it run at a constant 60Hz ±.2Hz, both at no-load and under load.

[pcfrisch]

The problem is that your meter probably isn't a "true rms" meter. The sine wave from the generator is somewhat ugly. That is why your meter is having problems trying to read the frequency.
The specs on your model call for a freq. of between 61.5-62.5 HZ.
Your manual is here:http://zillerelectric.com/mm5/merchant.mvc?Screen=MANUALS

[Kelly Myers]

I checked it with the generator and it was a very unstable 178 hz. The meter was a very unstable up and down. The same results loaded or unloaded. I can't understand. Using a cheap Sears DVM that reads frequency. Thought it might be the meter, but why is the line steady.



Lets all be happy that its your meter, and not the generator, because 178hz would probably damage some items


Frequency is directly proportional to engine speed. On guardian air cooled generators, its 1 HZ for every 60 revolutions per minute. In a perfect situation, the generator should be running at 3600 rpm's. 3600/60 = 60HZ

178HZ x 60 = 10,680RPM's on the engine. This is how I know the meter is faulty.

FYI, "Overspeed" will kick in at aprox 71.5HZ, or 4230 RPM's.