Inverter (off-line or stand-by) - UPS configuration in which the inverter is parallel-mounted to the load supply line and backs up the mains. This configuration offers a substantial cost reduction but is applicable only to low outputs, under 3 kVA, because it results in an interruption lasting up to 10 ms during transfer and does not filter inrush currents.
Electrical Line Noise - Radio Frequency Interference (RFI) and Electromagnetic Interference (EMI) are unwanted electrical signals that produce undesirable effects in sensitive electronic equipment.
Metal Hydride - An intermetallic compound or alloy in which hydrogen has been absorbed; also, the negative electrode in a nickel-metal hydride battery.
Voltage Delay - Time delay for a battery to deliver the required operating voltage after it is placed under load.
Limiting Current - The maximum current drain under which the particular battery will perform adequately under a continuous drain. The rate is based on whatever drain rate reduces the running voltage to 1.1 volts.
Micro-outage (or micro-interruption) - Total loss in the supply of power for 10 ms.
Frequency Variation - A change in frequency of more than 3 Hz.