Frequency Controlled Switches
Frequency Controlled Switches
Frequency Controlled Switches
These are load control devices for off-grid power systems with renewable generation and generation sets or inverters which produce a variable frequency supply.
Used to switch on additional loads to take advantage of surplus renewable generation which cannot be stored. They respond to a rise in the system frequency caused by battery inverters signalling a high state of battery charge, or by low load on a generator with frequency droop.
Each switch will control one appliance and is wired into the cable supplying the appliance. They require no user intervention and will automatically switch the appliance on when the system frequency is high and switch it off when the frequency is low. The frequency setpoint can be adjusted during installation.
They incorporate a number of features to ensure stable operation of an islanded power system:
- Once the frequency goes above the switch-on setting there is a delay before the appliance is connected; the higher the frequency is above the setting, the shorter the delay.
- The switch-off setting is a lower frequency than the switch-on setting to ensure stability.
- Once the frequency goes below the switch-off setting there is a delay before the appliance is disconnected; the lower the frequency is beneath the setting, the shorter the delay.
Can control loads up to 13A (3kW at 230V; 1.5kW at 120V). The most appropriate loads are heaters (water heaters, storage heaters, space heaters). Appliances with pumps are not appropriate due to the potential for rapid switching of loads.
| Product Code | Description | Retail Price (ex VAT) |
|---|---|---|
| FCS-1-B | Frequency controlled switch, Independent type, IPP Box | £90.00 |
MY-PV AC ELWA-F Frequency Responsive Solar Immersion Heater
For use in off-grid systems to use surplus energy once a battery has become fully charged.
The ELWA-AC-F detects frequency rise of the inverter, if there is excess energy available and uses it for heating water.
Advantages
- AC ELWA-F uses energy that cannot be stored in the battery
- Linear power control 0 - 3.000W for maximum self-consumption
- The AC ELWA-F needs no communication cables to the inverter
- Sinusoidal current consumption (no thyristor)
- For AC off-grid systems with frequency-shift inverters eg. Sunny Island & Victron
| Product Code | Description | Retail Price (ex VAT) |
|---|---|---|
| ELWA-AC-F | PV AC water heating unit - frequency controlled | £562.00 |
