Greetungs All,
I have a small generator (700 watt, 850 surge) that I use to keep the
fridge running when the power is out. It is a robust unit made by
Robin and is at least 20 years old. It has an accurate analog
voltmeter on it. I tested it by comparing to a digital meter and by
directly connecting just the meter to the 115 volt, 60 Hz mains. The
label says that the generator puts out 60 Hz but when checked with an
oscilloscope (TEK 465B) it shows about 50 Hz. Even though the fridge
seems to run fine it sounds different than when operating from the
mains. The meter on it shows the voltage as being 115 volts and the
motor is running at the nameplate RPM. So what could be the reason for
the 'scope showing the lower Hz and is there anything I can do about
it? This generator uses brushes on a slip ring to energize the field
winding and has some type of transistorised voltage regulator.
Thanks,
Eric R Snow

On Tue, 19 Dec 2006 11:10:25 -0800, Eric R Snow wrote:
> Greetungs All,
> I have a small generator (700 watt, 850 surge) that I use to keep the
> fridge running when the power is out. It is a robust unit made by
> Robin and is at least 20 years old. It has an accurate analog
> voltmeter on it. I tested it by comparing to a digital meter and by
> directly connecting just the meter to the 115 volt, 60 Hz mains. The
> label says that the generator puts out 60 Hz but when checked with an
> oscilloscope (TEK 465B) it shows about 50 Hz. Even though the fridge
> seems to run fine it sounds different than when operating from the
> mains. The meter on it shows the voltage as being 115 volts and the
> motor is running at the nameplate RPM. So what could be the reason for
> the 'scope showing the lower Hz and is there anything I can do about
> it? This generator uses brushes on a slip ring to energize the field
> winding and has some type of transistorised voltage regulator.

It might have come from Europe or something - doesn't it have a nameplate
that tells you what the output freq. is _supposed_ to be?

It might be as simple as an RPM adjust, since the voltage is regulated,
but anyone here would need much more information about the unit itself;
otherwise we'd just be guessing.

Thanks,
Rich

"Eric R Snow" <e...@whidbey.com> wrote in message 
news:k...@4ax.com...
> Greetungs All,
> I have a small generator (700 watt, 850 surge) that I use to keep the
> fridge running when the power is out. It is a robust unit made by
> Robin and is at least 20 years old. It has an accurate analog
> voltmeter on it. I tested it by comparing to a digital meter and by
> directly connecting just the meter to the 115 volt, 60 Hz mains. The
> label says that the generator puts out 60 Hz but when checked with an
> oscilloscope (TEK 465B) it shows about 50 Hz. Even though the fridge
> seems to run fine it sounds different than when operating from the
> mains. The meter on it shows the voltage as being 115 volts and the
> motor is running at the nameplate RPM. So what could be the reason for
> the 'scope showing the lower Hz and is there anything I can do about
> it? This generator uses brushes on a slip ring to energize the field
> winding and has some type of transistorised voltage regulator.
> Thanks,
> Eric R Snow
Small generators generally need to be adjusted so that the voltage and 
frequency are about 5 to 10 percent high with no load. Both will drop under 
load. I would try setting the engine speed up a bit. I would also suspect 
the oscilloscope calibration. The frequency cannot be incorrect when the 
engine speed is correct if it is a direct connected generator.

Don Young 

"Eric OR Snow"
>

> I have a small generator (700 watt, 850 surge) that I use to keep the
> fridge running when the power is out. It is a robust unit made by
> Robin and is at least 20 years old. It has an accurate analog
> voltmeter on it. I tested it by comparing to a digital meter and by
> directly connecting just the meter to the 115 volt, 60 Hz mains. The
> label says that the generator puts out 60 Hz but when checked with an
> oscilloscope (TEK 465B) it shows about 50 Hz.


**  Test it with an electric clock or clock radio.

  See how much time the clock loses over a few minutes.




.......  Phil

In article <4...@mid.individual.net>, p...@tpg.com.au 
says...
> 
> "Eric OR Snow"
> >
> 
> > I have a small generator (700 watt, 850 surge) that I use to keep the
> > fridge running when the power is out. It is a robust unit made by
> > Robin and is at least 20 years old. It has an accurate analog
> > voltmeter on it. I tested it by comparing to a digital meter and by
> > directly connecting just the meter to the 115 volt, 60 Hz mains. The
> > label says that the generator puts out 60 Hz but when checked with an
> > oscilloscope (TEK 465B) it shows about 50 Hz.
> 
> 
> **  Test it with an electric clock or clock radio.
> 
>   See how much time the clock loses over a few minutes.
> 

What would that accomplish above and beyond looking at the signal with 
an O'scope?  I would think the scope would be the preferred method and 
the clock using the 60Hz as a timbase would be the "I a'int got no 
scope" option.  If his O'scope showed about 50Hz I would think it is 
about 50Hz.

                   Jim

On Tue, 19 Dec 2006 21:36:59 -0600, "Don Young" <n...@nonesuch.com>
wrote:

>
>"Eric R Snow" <e...@whidbey.com> wrote in message 
>news:k...@4ax.com...
>> Greetungs All,
>> I have a small generator (700 watt, 850 surge) that I use to keep the
>> fridge running when the power is out. It is a robust unit made by
>> Robin and is at least 20 years old. It has an accurate analog
>> voltmeter on it. I tested it by comparing to a digital meter and by
>> directly connecting just the meter to the 115 volt, 60 Hz mains. The
>> label says that the generator puts out 60 Hz but when checked with an
>> oscilloscope (TEK 465B) it shows about 50 Hz. Even though the fridge
>> seems to run fine it sounds different than when operating from the
>> mains. The meter on it shows the voltage as being 115 volts and the
>> motor is running at the nameplate RPM. So what could be the reason for
>> the 'scope showing the lower Hz and is there anything I can do about
>> it? This generator uses brushes on a slip ring to energize the field
>> winding and has some type of transistorised voltage regulator.
>> Thanks,
>> Eric R Snow
>Small generators generally need to be adjusted so that the voltage and 
>frequency are about 5 to 10 percent high with no load. Both will drop under 
>load. I would try setting the engine speed up a bit. I would also suspect 
>the oscilloscope calibration. The frequency cannot be incorrect when the 
>engine speed is correct if it is a direct connected generator.
>
>Don Young 
>

To remove any doubt about the scope calibration, sync the scope
horizontal sweep to commercial power, and look at the generator
output.  When the engine speed is correct, the waveform on the scope
should be stable, or drifting very slowly one way or the other.

"James Beck"

>>
>> > I have a small generator (700 watt, 850 surge) that I use to keep the
>> > fridge running when the power is out. It is a robust unit made by
>> > Robin and is at least 20 years old. It has an accurate analog
>> > voltmeter on it. I tested it by comparing to a digital meter and by
>> > directly connecting just the meter to the 115 volt, 60 Hz mains. The
>> > label says that the generator puts out 60 Hz but when checked with an
>> > oscilloscope (TEK 465B) it shows about 50 Hz.
>>
>>
>> **  Test it with an electric clock or clock radio.
>>
>>   See how much time the clock loses over a few minutes.
>>
>
> What would that accomplish above and beyond looking at the signal with
> an O'scope?


**  A scope trace may be out of calibration, maladjusted or misread.


> I would think the scope would be the preferred method and
> the clock using the 60Hz as a timbase would be the "I a'int got no
> scope" option.


**  The clock method is vastly more precise and fool proof.


> If his O'scope showed about 50Hz I would think it is
> about 50Hz.


 **  Time to improve your thinking  -   fuckhead.




.......   Phil

"Phil Allison" <p...@tpg.com.au> wrote in message 
news:4...@mid.individual.net...
>
> "James Beck"
>
>>>
>>> > I have a small generator (700 watt, 850 surge) that I use to keep the
>>> > fridge running when the power is out. It is a robust unit made by
>>> > Robin and is at least 20 years old. It has an accurate analog
>>> > voltmeter on it. I tested it by comparing to a digital meter and by
>>> > directly connecting just the meter to the 115 volt, 60 Hz mains. The
>>> > label says that the generator puts out 60 Hz but when checked with an
>>> > oscilloscope (TEK 465B) it shows about 50 Hz.
>>>
>>>
>>> **  Test it with an electric clock or clock radio.
>>>
>>>   See how much time the clock loses over a few minutes.
>>>
>>
>> What would that accomplish above and beyond looking at the signal with
>> an O'scope?
>
>
> **  A scope trace may be out of calibration, maladjusted or misread.
>
>
>> I would think the scope would be the preferred method and
>> the clock using the 60Hz as a timbase would be the "I a'int got no
>> scope" option.
>
>
> **  The clock method is vastly more precise and fool proof.
>
>
>> If his O'scope showed about 50Hz I would think it is
>> about 50Hz.
>
>
> **  Time to improve your thinking  -   fuckhead.
>
>
>
>
> .......   Phil
>
>
>
>
>
Phil,
Take you medicine. 

"Tom Biasi " =  Jerk Off Scumbag


 Go choke on a dog turd -   cuntbrain.

Peter Bennett <p...@somewhere.invalid> wrote in
news:o...@news.supernews.com: 

>On Tue, 19 Dec 2006 21:36:59 -0600, "Don Young" <n...@nonesuch.com>
>wrote:
>
>>
>>"Eric R Snow" <e...@whidbey.com> wrote in message 
>>news:k...@4ax.com...
>>> Greetungs All,
>>> I have a small generator (700 watt, 850 surge) that I use to keep
>>> the fridge running when the power is out. It is a robust unit made
>>> by Robin and is at least 20 years old. It has an accurate analog
>>> voltmeter on it. I tested it by comparing to a digital meter and by
>>> directly connecting just the meter to the 115 volt, 60 Hz mains. The
>>> label says that the generator puts out 60 Hz but when checked with
>>> an oscilloscope (TEK 465B) it shows about 50 Hz. Even though the
>>> fridge seems to run fine it sounds different than when operating
>>> from the mains. The meter on it shows the voltage as being 115 volts
>>> and the motor is running at the nameplate RPM. So what could be the
>>> reason for the 'scope showing the lower Hz and is there anything I
>>> can do about it? This generator uses brushes on a slip ring to
>>> energize the field winding and has some type of transistorised
>>> voltage regulator. Thanks,
>>> Eric R Snow
>>Small generators generally need to be adjusted so that the voltage and
>>frequency are about 5 to 10 percent high with no load. Both will drop
>>under load. I would try setting the engine speed up a bit. I would
>>also suspect the oscilloscope calibration. The frequency cannot be
>>incorrect when the engine speed is correct if it is a direct connected
>>generator. 
>>
>>Don Young 
>>
>
>To remove any doubt about the scope calibration, sync the scope
>horizontal sweep to commercial power, and look at the generator
>output.  When the engine speed is correct, the waveform on the scope
>should be stable, or drifting very slowly one way or the other.
>
>
>
>
>

or look at the powerline frequency on the scope, if its ok then the other 
measurement is likely ok....

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----