GE SX TRANSISTOR CONTROL IC3645SR4U404N2 - Manual (Page 8)

BASIC OPERATION AND FEATURES
SX TRANSISTOR CONTROL Page 8
January 2000
Section 2.1.7 On-Board Coil Drivers & Internal Coil
Suppression
Coil drivers for the LINE and SP contactors
are on-board the control card. These contactors must have
coils rated for the vehicle battery volts.
Section 2.2 System Protective Override
Section 2.2.1 Static Return to Off (SRO)
This inherent feature of the control is designed to require
the driver to return the directional lever to the neutral
position anytime he leaves the vehicle and returns.
Additionally, if the seat switch or key switch is opened, the
control shuts off and cannot be restarted until the
directional lever is returned to neutral. A time delay of
approximately 2 seconds is built into the seat switch input
to allow momentary opening of the seat switch, if a bump is
encountered.
Section 2.2.2 Accelerator Volts Hold Off
This feature checks the voltage level at the accelerator
input whenever the key switch or seat switch is activated.
If, at start up, the voltage is less than 3.0 volts, the control
will not operate. This feature assures that the control is
calling for low speed operation at start up.
Section 2.2.3 Pulse Monitor Trip (PMT)
The PMT design contains three features which shut down,
or lock out, control operation if a fault conditions occurs
that would cause a disruption of normal vehicle operation:
• = Look ahead
• = Look again
• = Automatic look again and reset
The PMT circuit will not allow the control to start under the
following conditions:
• = The control monitors both armature and field FET's at
start-up and during running.
• = The control will not allow the line contactor to close at
start-up, or will drop it out during running, if either the
armature or field FET's are defective, so as to cause
uncontrolled truck movement.
Section 2.2.4 Thermal Protector (TP)
This temperature sensitive device is internal to the power
transistor (Q1) module. If the transistor's temperature
begins to exceed the design limits, the thermal protector
will lower the maximum current limit, and maintain the
transistors within their temperature limits. Even at a
reduced current limit, the vehicle will normally be able to
reach sufficient speed. As the control cools, the thermal
protector will automatically reset, returning the control to
full power.
Section 2.2.5 Low Voltage
Batteries under load, particularly if undersized or more
than 80 percent discharged, will produce low voltages at
the control terminals. The SX control is designed for use
down to 50 percent of a nominal battery voltage of 36-84
volts, and 75 percent of a nominal battery voltage of 24
volts. Lower battery voltage may cause the control to
operate improperly, however, the resulting PMT should
open the Line contactor, in the event of a failure.
Section 2.3 Diagnostics
Section 2.3.1 Systems Diagnostics
The control detects the system's present operating status
and can be displayed to either the Dash Display or the
Handset. There are currently over 70 status codes that are
available with SX systems using Traction and Pump
controls and Truck Management Module (TMM). Along
with the status code display from the TMM, the SX control
is capable of reducing the current to the motor, alerting the
operator of a critical fault condition.
Section 2.3.2 Status Codes
Section 2.3.2a Standard Status Codes
The SX traction control has over 30 Status Codes that
assist the service technician and operator in trouble
shooting the vehicle. If mis-operation of the vehicle occurs,
a status code will be displayed on the Dash Display for
vehicles so equipped, or be available by plugging the
Handset into the “y” plug of the logic card.
With the status code number, follow the procedures
outlined in DIAGNOSTIC STATUS CODES to determine the
problem and a solution.
Note: The Status Code Instruction Sheets do not claim to
cover all possible causes of a display of a "status code ".
They do provide instructions for checking the most direct
inputs that can cause status codes to appear.
Section 2.3.2.b Stored Status Codes
This feature records the last 16 "Stored Status Codes" that
have caused a PMT controller shut down and/or disrupted
normal vehicle operation. (PMT type faults are reset by
cycling the key switch). These status codes, along with the
corresponding BDI and hourmeter readings, can be
accessed with the Handset, or by using the RS 232
communications port and dumping the information to a
Personal Computer terminal.