Transfer Switch Maintenance

Due to the extensive nature of the services below, the below services must be performed with a de-energized ATS contactor and control system. While certain switch types allow for this type of maintenance without interruption of service, on most standard ATS the level of services described below will require the switch to be de-energized. This means that both utility service and generator service will be unavailable for the duration of the maintenance and all downstream equipment will be off-line. We will certainly be willing to work with you to minimize impact to your business by coordinating services at the least inconvenient time for you.

AUTOMATIC TRANSFER SWITCH (ATS) MAINTENANCE

Actuators – Observe actuators and control arms and note any indications of mechanical binding or inhibitors.
Cabinet/Enclosure – Wipe interior of enclosure and remove accumulated dust and/or dirt. If excessive dust or debris is present, recommend more extensive ATS service.
Cabinet Door and Seals – Check door closure, seals, hinges, locking bar and lock mechanism for signs of wear and proper operation.
Contacts and Connections – Visually inspect normal and emergency arcing contacts and main contacts for indications of wear, debris or buildup and clean as necessary. Recommend replacement if necessary. Check temperature of all stationary and movable contactors with infrared thermometer once re-energized.
Control Wiring and Connections – Inspect all control wiring for indications of wear, insulation deterioration, tracking, overheating or loose connections. Tighten where necessary.
Ground Wiring - Check all common and ground wires, measure and record resistance to ground (Ω).
Load Cabling – Visually inspect building, normal source and emergency source for indications of deterioration. Check lug connections and mounting insulator bolts.
Relays - Calibrate all phase and voltage sensitive relays.
Transfer Switch Controls – Visually inspect for proper operation of digital or analog controls. Note any non-operational indicator bulbs, meters, switches or digital user interface controls.
Time Delays and Controls – Observe all time delays during simulated test. Ensure time delays are set within manufacturer recommendations or are concurrent with or building or generator application requirements.
1. Time Delay to Start – Delay to prevent engine start during momentary losses or “brown-outs”. Recommended to be set to between zero and one (0-1) second.
2. Time Delay to Transfer – Delay between when equipment has stabilized at operating frequency and voltage and switch actuating to emergency source. Recommended to be set between zero to five seconds (0-5). See note below.
3. Time Delay to Re-Transfer – Delay between utility being restored and switch actuating from emergency to utility source. This prevents re-transfer before a stable utility source is deemed present. Recommended at a minimum of five (5) minutes.
4. Time Delay for Cool-down – Delay to allow generator to operate in an unloaded condition to allow equipment to cool down for safe shut down. Recommended in accordance with manufacturer’s recommendations or for a minimum of 15 minutes.