New Genset Trips On Overspeed at Startup

First of all our diesel engine is equipped with an EGB-13P governor/actuator.
One of our test consists in simulating a failure of the electronic speed control module and check if the EGB-13P can take over and start up the engine.

Unfortunately, in this situation the hydraulic governor EGB is too slow to respond causing an overshoot at the startup. More than 10% of the rated speed. We've got in touch with Woodward, but the only advice they gave us so far is to adjust the needle valve.

In order to adjust it, we started the engine with a low speed setpoint then went up slowly to rated.

We noticed that when this valve is widely open the engine is hunting like crazy. So we closed a little the valve to adjust the hunting to an acceptable level of +/-1%. Actually, we are not sure whether or not this hunting is unsafe for the genset.

Despite this adjustment we still have the same problem of overspeed at startup. Our records show a little improvement in the overshoot which is now about 9%.

Also, there is this guy with us saying that the EGB is not made/designed to take over if the failure happens when the engine is not already running at rated speed. He says that we will always trip on overspeed if there is no load to "slow down" the engine at the moment of the failure.

Any help is welcome.

You need to download and read the Product Data Sheet for the EGB-13P, because it seems to very clearly state that an electronic, digital or pneumatic device is required to start the machine. The EGB-13P appears to take a signal from any one of those types of devices and convert it to a fuel flow-rate to the prime mover. And, that the EGB-13P is designed to shut the prime mover down in the event of a failure of the control providing the fuel flow-rate signal to the EGB-13P. (A lot of Woodward documentation is not very clear; but that can be said of many power generation equipment manufacturers, not just Woodward.)

There appears to be a way to limit the genset output in the event of loss of the control signal to the EGB-13P but then the EGB-13P is supposed to safely shutdown the prime mover/genset.

That's from a very quick read of the data sheet. It's primarily a means for driving the actuator of the fuel control valve based on a signal from some other control system (governor). It's not really reasonable to expect the device to be able to start or even operate (continuously) the prime mover/genset in the event of a failure (loss) of the main control system. For something like this, you should really have redundant controllers or something similar.
Dear Saulguy,

As this is a new Diesel engine powered generator, please check your droop compensation CT connection to AVR. Reversed S1 and S2 connection causes engine speed to keep increasing at start, and engine will stop of over frequencies or overspend.

By reversing S1 and S2 connection to AVR your problem will be resolved.

Good Luck.

Sanjay Rana
[email protected]