Hydrolic Amplifier

[Nemara]

Hi guys,
In my plant there is a steam turbine for a hydrogen compressor the problem is there is a fluctuation in the turbine speed.
does anyone faced a same phenomena the hunting is caused by the vendor recommendation by the oil supply for the Woodward hydraulic amplifier, the governor is an electronic Woodward 505 for controlling the speed.

 

[gerhardl]

I have no experience in this product range.

Googling the Howard specifications

http://www.woodward.com/SteamTurbineHydAmp.aspx

(go from this page and see the detailed description)

I am guessing at two possibilities, or both combined:

1. The oil is not sufficiently controlled at upstart, see necessary force at low pressures/speeds and recommendations.

And/or

2. Where / how is the milli-ampere steering signal originated or picked up? Is this done, or placed, in such a way that it in itself is stabilized, and not likely to give overcompensation with following undercompensation?

Best wishes!

 

[Nemara]

Dear Gerhardl,
I appreciate your reply

1. The oil is not sufficiently controlled at upstart, see necessary force at low pressures/speeds and recommendations.
- [highlight #EF2929]The oil pressure supply is sufficient nd stable at 10 bar we use an accumulator with nitrogen for blanketing the oil from fluctuations also the oil have been replaced.[/highlight]
2. Where / how is the milli-ampere steering signal originated or picked up? Is this done, or placed, in such a way that it in itself is stabilized, and not likely to give overcompensation with following undercompensation?
- I understand what you means the milliamp Is stable we did a loop check and stroke the actuator stem by an external milliamp source Woodword uses an EG-3P converter.
i'll keeps you updated as soon as we reach the root cause

 

[gerhardl]

OK! More ideas: Any possibility of nitrogen or air bubbles in the hydraulic system? Ports and pipelines for oil too large or too small? Any backlash in the system? Non return valves in oil-pipes necessary or if present OK?