30 Minute and 4 Hour Transfer Tests

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The following services are included in both a 30 minute and a 4 hour transfer test but are based on functionality of the automatic transfer switch, on-site personnel being present and the authorization to perform a simulated power failure.  While utility source will remain present for all other building circuits, all circuits fed from automatic transfer switch will transfer from utility source to emergency (generator) power.  The duration of this test is the maximum time required to record all measurements indicated below (typically the duration of the test +30 minutes, including engine cool-down cycle).

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1. Alarms and Controls - Ensure no alarms are present at generator control panel, remote annunciator and at ATS control panel prior to initiating test.  

2. Initiate Test - Initiate transfer test utilizing one of the following methods:

   1. Transfer at ATS Control Panel (preferred method) – Either through pre-programmed controls on digital control panel or at “test” switch on analog control panel, initiate simulated power failure.

   2. ATS Disconnect Switch – Locate in-line ATS disconnect switch (if equipped) and open switch to remove utility power from normal source at ATS. 

   3. Distribution Panel – Locate utility distribution panel breaker feeding ATS and open to remove utility power from normal source at ATS.

3. Initial Time Delays – Observe 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.

4. Record Loaded Measurements – Once operating on emergency (generator) power, record under initial power the following readings:

   1. Engine Oil Pressure – Measure and record engine oil pressure (PSI)

   2. Engine Fuel Pressure – Measure and record engine fuel pressure (PSI)

   3. Engine Water Temperature - Measure and record engine water temperature (F).

   4. Voltage – Measure and record unloaded AC voltage (V).

   5. Frequency – Measure and record unloaded frequency (A).

   6. Amperage – Measure and record unloaded amperage (Hz).

   7. Repeat in 15-minute intervals for duration of test.

5. Return to Utility -  Initiate end to transfer test sequence by one of the following methods:

   1. Transfer at ATS Control Panel (preferred method) – Either through pre-programmed controls on digital control panel or at “test” switch on analog control panel, initiate end sequence to simulated power failure.

   2. ATS Disconnect Switch – Close ATS disconnect switch to restore utility power to normal source at ATS. 

   3. Distribution Panel – Close distribution panel output breaker on feeding ATS to restore utility power to normal source at ATS.

6. Final Time Delays – Observe time delays after simulated test.  Ensure time delays are set within manufacturer recommendations or are concurrent with or building or generator application requirements.

   1. 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. 

   2. 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.

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