Description
Solar First Transfer Switch, Controlled by Electronic Timer
by MySite Energy
This Cummins Service Entrance rated 200A transfer switch provides solar-first power to loads, with automatic switching to utility power based on timer set-point. Transfer adjustable using built-in digital timer. Timer settings are defined by user.
Ideal for switching to solar during times of peak utility pricing. Otherwise, utility is connected to inverter AC input
When not in the active switched condition, the utility input reverts to supply power to the inverter’s AC input. This enables battery charging or pass through by power inverter.
Enables automatic switch to utility power when lithium batteries shut down.
Also enables fire personnel to switch off the utility and solar energy feeds at one location. This is one of the few switches that ensure maximum protection to first responders.
The Intelligent Transfer Switch is activated at the set timing and the AC voltage coming from the solar system. Excessive drop in battery voltage OR loss of AC power, will cause transfer to the incoming utility power.
The utility supply your home is maintained until the timer setting interval has ended AND the solar AC power resumes. When the solar system output resumes, the transfer switch automatically switches from utility power, back to the solar power.
Features
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Uses solar as primary source, and utility as backup
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Simple 2-wire battery connection
- Reverts to utility power when lithium battery enters sleep mode
- AC breaker to disable utility and toggle switch to disable solar
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Steel enclosure is NEMA 3R outdoor rated
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200-amp, Volts: 240; Poles: 2
- RMS Symmetrical Amps at 240 VAC: 22,000A
- Dimensions: 23.3″ x 19.8″ x 7.2″, weight 58lbs
Solar-Controlled Transfer Switch, software controlled from 12V to 48V battery voltage level.
Electrical diagram of Solar battery controlled transfer switch

Timer for settings control of transfer switch