The ATC-300+ is a comprehensive and multifunctional microprocessor-based ATS controller. It is a compact and self-contained panel-mounted device that is designed to replace traditional relay and solid-state logic panels. The ATC-300+ Controller provides programmed flexibility to address the needs of any system. It operates from all system voltages between 120 to 600V, single-phase and three-phase at 50 or 60 Hz. In addition, a period of no control power is provided. The controller monitors the condition of the three-phase line-to-line voltage and frequency of Source 1 and Source 2 power sources and can be programmed for single-phase operation. The ATC-300+ Controller provides the intelligence to ensure that the ATS operates properly through a series of programmed sensing and timing functions.

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Technical Summary

Rating Range
120 to 600V, single phase and three phase @ 50/60 Hz
Transfer Type
Switch application dependent
Switch Type
Switch application dependent

ATC Controller Specifications

Input control voltage
65 to 145 Vac 50/60 hZ
Voltage measurements of Utility
Source 1 VAB Source 2 VAB
Source 1 VAC Source 2 VBC
Source 1 VCA Source 2 VCA
Voltage measurement range
0 to 790 VAC rms (50/60 Hz)
Voltage measurement accuracy
+/-2% of nominal input voltage
Frequency measurements of
Source 1 and Source 2
Frequency measurement range
40 Hz to 70 Hz
Frequency measurement accuracy
+/- 0.1 Hz
Undervoltage dropout
50% to 90% of nominal voltage
Undervoltage pickup
(Dropout +2%) to 99% of the nominal system voltage
Underfrequency dropout range
90 to 97% of the nominal system frequency
Underfrequency pickup range
(Dropout +1 Hz) to 99% of the nominal system frequency
Overfrequency dropout range
103 to 110% of the nominal system frequency
Overfrequency pickup range
101% to (dropout - 1 Hz) of the nominal system frequency
Operating temperature range
-20 to 70 degree C (-4 to +158 degree F)
Storage temperature range
-30 to 85 degree C (-22 to +185 degree F)
Operating humidity
0 to 95% relative humidity (noncondensing)
Operating environment
Resistant to ammonia, methane, nitrogen,hydrogen and hydrocarbons
Generator start relay
5A, 1/6 hp @ 250 Vac Vac 5A @ 30 Vdc with a 150W maximum load
K1, K2 relays

10A, 1-3 hp @ 250 Vac

10A@30 Vdc
Applicable testing
UL-recognized component
Meets intent of UL 991 & UL 1008
Meets IEC 1000-4-2, 1000-4-3, 1000-4-4
Applicable testing continued
1000-4-5, 1000-4-6, 1000-4-11
CISPR 11, Class A
FCC Part 15, Class A
CSS 22.2-178
Enclosure compatibility
NEMA 1, NEMA 3R and NEMA 12
UV-resistant ATC-300+ faceplate