MAN B&W 5L28/32H, Руководство пользователя, Страница: 167 / 218

08028-0D/H5250/94.08.12
1635436-4.2
Page 1 (2)
Converter for Engine RPM Signal B 19 13 1
General
Engine RPM signals
For measuring the engine's RPM, a pick-up mounted
on the engine is used giving a frequency depending
on the RPM. To be able to show the engine's RPM
on an analogue tachometer, the frequency signal is
sent through an f/I converter (frequency/current
converter), where the signal is transformed into a
proportional 4-20 mA ~ 0-1200 RPM.
Both tachometer on the engine and possibly external
tachometers should be connected in the current
loop.
Further, the converter has following signals:
– overspeed
– engine run
– safe start
– tacho fail
Overspeed
When the engine speed reach the setpoint for
electronic overspeed the converter gives a shutdown
signal and a alarm signal through a relay.
94.04
Engine run
When the engine speed reach 710 RPM the conver-
ter gives a "engine run" signal. The signal will also
be given when the engine speed reach 200 RPM +
8 sec., (this is used for pump engines).
The engine run signal will be deactivated when the
speed is 640 RPM. If the engine speed haven't been
over 710 RPM the signal will be deactivated at 200
RPM.
The "engine run" signals will be given through a relay.
One for synchronizing and one for start/stop of pre.
lub. oil pump or alarm blocking at start/stop.
Safe start
When the safe start signal is activated the engine
can start. When the engine reach app. 140 RPM the
air starter will be shut-off.
Further, the safe start signal is a blocking function
for the air starter during rotation.
Fig. 1. Converter for engine RPM.