Emergency inverters connected to a dedicated emergency fixture or circuit always needs an unswitched power source connected to the inverter. This allows the inverter to maintain the onboard batteries in a state of readiness to power the connected load during a loss of normal power.
The impact of this requirement means that, in some cases, the connected load to the inverter would also receive unswitched power (meaning no local ability to switch or dim the lighting.)
This problem can be solved in two different ways, depending on the inverter design:
1) Using two sets of input leads: one set of leads connecting to the unswitched input and second set (sometimes referred to as the 'flying leads') that connect to the switch. This method allows the inverter to maintain the battery, while also recognized local switch positions for the connected load.
2) If the inverter design does not feature two sets of input leads, then an ALCR (Automatic Load Control Relay) device, such as an ETS DR, can be used to shunt emergency power around the switch during a loss of normal power.
Inverters and Secondary 0-10V Dimming Signals
If a 0-10V dimmer is present, then the inverter can bypass the 0-10V signal to allow the emergency load to operate at full brightness. This can be achieved either by the presence of dimming relay leads on the inverter or by using an ETS DR device (which includes a Dimming Relay lead) to bypass the signal.
Some IOTA inverter models include a Dimming Relay (DR) function also, eliminating the need for secondary device for this purpose.
To help you select the right inverter model for your application, or to understand if an ETS DR is a good fit for your current IIS inverter, refer to the chart below: