MoTeC PDM30 - Manual (Page 14)

MoTeC Installation 11
Electronic Devices
The PDM can supply power to electronic devices such as engine
management systems, data acquisition systems, radios etc.
Many electronic devices will have a short inrush current. The PDM will largely
ignore this due to the Output Load filtering. See the Over-Current Shutdown
section for details.
The PDM provides reverse battery protection and load dump clamping to
protect itself and the connected devices.
Ignition Systems
Inductive Ignition Systems
Most inductive ignition systems draw a peak current of about 8 ampere,
some draw as much as 20 ampere; however the average current is much
lower.
In most cases inductive ignition systems can be connected to an 8 Amp
output however the Output Load current must be checked to ensure it
stays well clear of 100%.
The average current will increase with increasing RPM so the Output Load
should be checked at maximum RPM.
CDI Ignition Systems
CDI ignition systems can draw peak currents of as much as 50 ampere. It
is recommended that all CDI ignition systems are connected to a 20 Amp
output.
The average current will increase with increasing RPM so the Output Load
should be checked at maximum RPM.
Engine Management Systems
The current drawn by an engine management system will depend on the type
of loads it is connected to and the operating conditions.
Fuel injectors draw current in pulses. The maximum average current drawn by
the fuel injectors is when they are at maximum duty cycle.
For servo devices such as Drive by Wire motors maximum current is drawn
when making large transitions.
Check that the Output Load is clear of 100% under worst case operating
conditions, i.e. when the injectors are operating at maximum duty cycle, servo
devices are making large transitions and any auxiliary loads are drawing
maximum current.