Catapiller 125kw, Oil step speed?

[BamBam.a]

Hi Guys,

Does anyone know what "Oil step speed" is?

As I understand it; the MPU counts the flywheel teeth which in turn gives you your RPM
of the engine. Some how this is then gives a reading of the Oil Step speed, but I have no idea what this is.

I don't imagine the oil pump has a stepper as it should be driven right off the crank.

Any input?

 

[TugboatEng]

Cat uses two different oil pressure alarm setpoints. The step speed may be something like 1000 rpm and the oil pressure alarm sounds at 15 psi below 1000 rpm and 45 psi above. These are just example numbers and do not represent your specific case.

 

[catserveng]

Oil Step Speed was used on larger engines, mainly 3500 and 3600 series engines that had a priority valve in the lube oil system, at 125kW your engine won't.

Attached is a calibration procedure.

Hope that helps, MikeL.

 

[catserveng]

Should have asked you what engine you have and if you're using the the speed switch for the governor oil pressure switch. If the oil step contacts are not being used you can ignore the calibration for it. If they are being used you need to specify for what so the right step speed can be set.

MikeL.

 

[BamBam.a]

Tugboat, Catserveng, Thanks guys, for your answers.

So if I understand this right, the oil step is a "switch" of sorts that at a certain rpm either closes or opens a circuit that has to do with the lube system, to either show an alarm
or to increase/decrease the pressure. ?

The engine is an XQ125. 3304 TA - 4 stroke Turbocharged.

Im not having any issues with the engine, I just read about the Oil step in the manual and I have never come across this particular term before, so Im just trying to
get the term "oil step" defined and understood.

 

[catserveng]

The "Oil Step" switch was introduced on the second generation CAT ESS (Electronic Speed Switch), it's main purpose was to provide a second level low oil pressure shutdown point on the 3500 series engine. The 3500 series were the first CAT engines to use a piston cooling jet priority valve, at lower speeds resulting in lower oil pressures, the priority valve shut off oil flow to the piston cooling jets, so a lower pressure low oil pressure shutdown switch was required to properly protect the engine when the priority valves was closed, but that pressure switch setpoint was too low for the engine operating at higher speeds with the priority valve open. So the Oil Step Switch was used to activate a higher pressure set low oil pressure switch above a certain RPM setpoint.

Shortly after that feature was introduced, CAT started to use it on other electric power (and some industrial) engines to arm other parts of the older ETS and ETR protection systems. Once the newer electronic control panels came into production the use of that switch dropped of across the board. But still a bunch in use.

Hope that answered the question to your satisfaction,

MikeL.