Thermal Protection Device; Rheostat For Remote Voltage Setting; Instructions For Manual Control Of Generators - MarelliMotori M8B 315 Instructions And Safety Information

Use of microswitches
To change the stability characteristics of the regulator, it is possible to use the microswitches.
In such a way it is possible to insert capacitors on electronic stability circuit, then obtaining step changes in the transient response of
the regulator.
dip 1
⇒ speed response becomes slower
pos.ON
dip 2
⇒ speed response becomes slower
pos.ON
dip 3
⇒ standard low speed protection
pos.ON
dip 4
dip 5 not used

5.1. Thermal protection device

The generators are equipped with a thermal protection device against dangerous overloads. This device is connected to the auxiliary
terminals E-C, and can be used by the customer as command for either alarm or intervention. The terminals E-C have normally closed
contact for 250V - 5A.
This device does not act on regulation system (AVR).

5.2. Rheostat for remote voltage setting

For all generators, that rheostat can be inserted between the auxiliary terminals P and Q (FAST-ON terminals) of the AVR after having
removed the short-circuiting bridge. The external rheostat has to be inserted with its wiper in intermediate position and then the internal
potentiometer of AVR (P1) has to be reset to obtain the nominal voltage.

5.3. Instructions for manual control of generators

If the voltage regulator (AVR) breaks down, a manual control system can be used, when a 24 V D.C. power supply is available.
This source could consist of a bank of batteries or of a voltage transformer and a rectifier unit connected at the alternator output.
- disconnect the two exciter stator terminals (red wire +, blue wire -) from AVR
- apply the D.C. power supply to these two wires
- set the rheostat R to adjust the alternator output voltage.
WARNING: compensate by manually increasing excitation as the load increases.
Before removing the load, reduce the excitation current
Use the following table to select the rheostat:
Generator
M8B 315
M8B 400
M8B 500
BLUE
EXCITER
STATOR
WINDING
TERMINALS
RED
I max Max. resistance of rheostat
[A]
4
6
8
⇒ proportional low speed protection V/f
pos.OFF
24 V
R
[Ω]
80
80
80
17
ENGLISH