Parrelleing Cat engines 1

[pedersonpoint]

A metal recycling customer that has two Caterpillar 3516A mechanical engines "NOT" generators. The engines are coupled to a pulley system through air clutches that simultaneously engage putting the machines in parallel. Both engines have 2301A short board speed controls that drive EG10P actuators. The engines do not proportionally loadshare do to the misapplication of the type of speed control used.
Woodward does offer a 723 speed control that uses a 4-20 ma input from a rack position sensor or from a 4-20 ma output from a manifold air pressure transducer.
Does anyone know of a cheaper alternative then using two Woodward 723s

 

[niallnz]

If you wan to retain the 2301's you will have to add an external controller (PLC)and sensors for rack position or air pressure. My preference is for rack/actuator position but it will have to be installed well due to the vibration. The 2301's will have to operate in droop and the PLC will adjust the speed trim input one one engine such that the rack positions are the same.

You will have to tell the PLC that one engine is the master. The PLC will monitor the master rack position and try to match the slave rack position by adjusting the speed setpoint. This is what the 723 mech loadsharing controller does but it is configured so that either engine can be the master (which can be switched on the fly) and automatically does speed matching for clutch in control.


Fun project.
Cheers Niall

 

[waross]

Install the droop option on both 2301's. Set the droop the same on both boards. Set the speed the same on both engines. Bring both engines up to speed, engage the clutches and go to work. The no-load speed may be set high by about the same PU as the droop so that under load the engines will drop to the desired speed.
If you need speed changes under load, change the input signal to both boards simultaneously.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[catserveng]

The droop method works ok, only drawback is if one engine starts to have problems a large imbalance can occur.

2301 (or any electronic speed control)with some additional control and sensors can work, but you'll need to assure that both engines get setup as close to the same as possible every time. Had a twim marine system that everytime one of the engines got a "tuneup" the techs were not careful in assureing actuator and fuel linkage travels were properly matched.

Woodward has a 723 (actually an 828 frame with a custom program) for tandem engines that can be used for your application, a single controller, two actuator outputs, MAP sensor inputs, and monitor throttle position. The ones I did also had flexible couplings and we used two MPU's per unit for torsional monitoring. Not exactly cheap, but I think with that much horsepower running in that kind of application do you really want to cut corners?

The Woodward folks in Holland have done a number of combined mechanical units in many different arrangements, maybe contacting your local Woodward reps and asking them to research for you?

Mike L.

 

[pedersonpoint]

Thanks to all! very helpfull.