Descriptions

Waveform

Possible Reasons

POWER FAILURE

A zero volt. for 2 cycles or more

Breaker tripped, main power failure, interruption of utility power distribution

POWER SURGES

>110% normal voltage for one cycle or more

Heavy electrical equipment turning off

VOLTAGE SPIKES

up to 6KV within a period of 1/10000 seconds to 1/2 cycles

Lightning, power switching, arch discharge, electrostatic discharge, large electrical equipment on-off

TRANSIENTS

up to 20KV within a period of a millionth to 1/10000 seconds

Lightning, power switching, arch discharge, electrostatic discharge, large electrical equipment on-off

POWER SAGS

Lower than 80%~85% normal voltage for one cycle or more

Starting up of Heavy loads or heavy electric machines/electrical motors

LINE NOISE

RFI, EMI and other high frequency interferences.

Electrical machines, relay, motor controlling machines, broadcasting emitting, microwave emitting, etc.

FREQUENCY VARIATION

> 3 Hz frequency alternation

The unstable operating of generator, unstable frequency of the utility power system.

BROWNOUT

Lower than a certain percentage of normal voltage

Starting up & application of Heavy equipment, utility power transferring, overloaded