Phase Three Modular (PTM) Concept
Emergency Vehicles are held to the highest degree of reliability and service performance, thus redundancy within systems builds in tolerance of points of failure without impacting the operation of the vehicle. This fault tolerance concept is employed in the PTM series chargers.

Recognizing that all equipment has a finite service life and random component failure can occur at any time, system reliability can be improved by reducing the number of single points of failure, thus diminishing the impact of a solitary fault on the overall system. The PTM series applies the “fault-tolerant” concept to battery chargers, by using multiple independent charger modules within the unit.

The PTM consists of a case which serves as connection point to AC input and battery bank output, as well as three front-facing power bays, each accommodating a 550 watt charger module which slides and locks in place. If a module fault occurs, a front panel indicator is activated and the system continues operating on the remaining modules.

Emergency personnel and vehicle service shops will both appreciate this system approach to DC system reliability. A dead charger can cause dead batteries and disable an emergency vehicle just when it is needed most. With the PTM redundant charging system a fault in one of the modules is easily identified and it can be quickly replaced with an on-hand spare or an exchange unit from the factory, all while the charging system continues to operate on the two remaining like modules.

The system features three stage charging for rapid recharge and optimal battery life. See Phase Thee Series for a complete description of the three stage charging process.