AC line generator (60 hz) characteristics

[ge]

We have a customer who's trying to run some of our uP-based equipment
on a 15KW gas-driven generator. Things are not going well. (Like,
our box won't boot. Oops.) We're still trying to get information
from him, and we're going to get a generator here, etc. But, there's
the big rush; so, in the meantime, I thought I'd enquire here.

The generator in question is "a step above consumer-grade." We know
the frequency is not dead-on 60 hz, but we don't think that should
create the problems they're seeing. Transients might, depending on
their characteristics - particularly at the zero-crossing point.

If anyone wanted to share their experience with the output quality of
these things, I'd appreciate it.

TIA,
George

 

[Roger Lascelles]

It is a brave act to plug sensitive equipment into a generator, without
first checking the situation.

The generator can kill your equipment too - zap it in a nasty way so even
when you switch to good power, you continue to get failures over time.

Of course, the basic solution is a UPS.

Roger


"ge" <e_c_l_e_s@a-znet.com> wrote in message
news:ij4sl0p9k2nu60od5hr1gs01g7cs56qk5g@4ax.com...

We have a customer who's trying to run some of our uP-based equipment
on a 15KW gas-driven generator. Things are not going well. (Like,
our box won't boot. Oops.) We're still trying to get information
from him, and we're going to get a generator here, etc. But, there's
the big rush; so, in the meantime, I thought I'd enquire here.

The generator in question is "a step above consumer-grade." We know
the frequency is not dead-on 60 hz, but we don't think that should
create the problems they're seeing. Transients might, depending on
their characteristics - particularly at the zero-crossing point.

If anyone wanted to share their experience with the output quality of
these things, I'd appreciate it.

TIA,
George

 

[nospam]

ge <e_c_l_e_s@a-znet.com> wrote:

We have a customer who's trying to run some of our uP-based equipment
on a 15KW gas-driven generator. Things are not going well. (Like,
our box won't boot. Oops.) We're still trying to get information
from him, and we're going to get a generator here, etc. But, there's
the big rush; so, in the meantime, I thought I'd enquire here.

Are they turning on your equipment by starting the generator? A slow
voltage buildup from a starting generator is something you would never see
on a mains supply.

 

[ChrisGibboGibson]

"Jeff" levy_jeff wrote:

[snip]

The governor can't compensate much, since diesels usually only control the
fuel amount for speed, and not the air quantity. Dump in uncontrolled, large
amounts of fuel into the intake, and the engine governor could only cut the
diesel fuel supply to an minimal amount (about idle amounts). Dump enough
fuel into the intakes, and the engine can uncontrollably produce more then
rated power, depending on the fuel, and how much the injector pump holds
back at wide open throttle (for several reasons, mostly pollution). Fuel
introduced this way is also very hard on the engine, due to uncontrolled
fuel delivery timing, which causes detonation and preigntion. Hot spots may
also form.

Welcome to sci.electronics.design.diesels

Sorry. Couldn't resist.

I actually found that quite interesting.

He's also correct. As I can confirm as the owner and maintainer of a vintage
Gardner diesel.

Gibbo

 

[ChrisGibboGibson]

ge e_c_l_e_s@a-znet.com wrote:

This statement ...

One other thing I've seen on many generators is a dip in the waveform down
to
around 10% voltage for 1 to 2mS duration at around 60 and 120 degrees.

This actually might cause us a great deal of trouble. Is it common
among generators? It seems fairly astounding. Do you know the
mechanism?

Yes it's *very* common. Many phase controlled circuits have *real* trouble
because of this. I've never looked into what causes it so I have no idea of the
mechanism. It does tend to diminish the higher the load.

Gibbo