Eaton ATC-300 - Testing and Problem Solving; Testing Procedures

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Instruction Booklet
Page 30 Effective: August 2010
ATC-300 2-Position Contactor
Based Transfer Switch
Figure 25. Dual Utility Transfer Switch.
Dual Utility Transfer Switch
Source 1 is available
Close Source 1
(Energize K1)
Source 1 is powering the load
Source 1 becomes unavailable
(or Go To Emergency)
Is Source 2
Available?
TDNE timer times out
Open Source 1
(Energize K2)
Close Source 2
(Energize K2)
Source 2 is powering the load
Is Source 1
Available?
TDEN timer times out
Ye s
No
No
Ye s
Open Source 2
(Energize K1)
Close Source 1
(Energize K1)
Source 1 is powering the load
Sends pretransfer signal
TPRE timer times out
(If Source 1 is Available)
Sends pretransfer signal
TPRE timer times out