5101 Engine Start Monitoring System
381333-474 C 3
General Information
Overview
A susceptible location for a control wiring fault is in the long distance wire run between a transfer switch’s locations to
the generator’s location. This wire run could travel through hundreds of feet of conduit in any part of a facility where
damage due to construction or other factors could go unnoticed for extended periods. This could result in generators
failing to start when called upon by transfer switches during outage conditions.
The ASCO 5101 Engine Start Monitoring System (5101-ATS/5101-GEN) is a system designed to forward engine start
signals while continuously monitoring for wiring faults according to the electrical code NEC 700.10. Typically, the
transfer switch control circuits use a relay contact to signal the generator to start. The transfer switch engine start contact
is connected to the generator using two wires. The generator and transfer switch may be close together or may be a long
distance apart. In some cases, a single transfer switch is used with a generator, but in other cases multiple transfer
switches may need to start the same generator.
During proper operation, the generator controls detect the relay state and determine if the generator should be started.
Depending on the system, the contact may either open or close to signal a start condition. The engine start relay has only
two states: open or closed. In the event that a fault occurs in the signal wiring, the generator start function may not
function properly.
The 5101 Engine Start Monitoring System uses two modules: (5101-ATS and 5101-GEN) one at each transfer switch and
one at the generator. The generator module receives the engine start signal from each ATS module (up to 8 modules) and
monitors for any faults in the wiring. If the 5101-GEN receives any engine start signal or if it detects any faults, it will
send the start signal to the generator and provide an alarm.
When used with switchgear or power control systems, the 5101 Engine Start Monitoring System should only be applied to
the wiring between the transfer switches and gear. The 5101 solution should not be applied between the power control
system and generator due to the fact that this is considered part of the generator control wiring and requires many more
critical signals to properly operate the generator beyond the traditional two wire engine start (ex. synchronization, breaker
control and cranking control signals, etc.).
Main Specifications
Parameter Description
DC Power 9-27V 15W max (Gen- Module) / ATS module does not
require power
Internal Ride Through Power 3 seconds minimum
Mounting 35mm DIN rail
Operating Temperature Range -20℃to 70℃
Maximum Distance 1000 feet one way from ATS to GEN (2000 feet loop)*
Maximum Wire Loop Resistance Resistance must be less than 100Ωohms
Generator Module Start Contact 1A 30VDC (Form C)
Generator Module Alarm Contact 1A 30VDC (Form C)
Wire Gauge 12-30 AWG stranded
*Contact ASCO Power Technologies for longer distances.
