Operation principle

UM0575

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1.3.2

ON state

As soon as the mains voltage is applied:

●

M1 is OFF because the voltage drop across the PTC is not high enough to reach the

DZ1 clamping level

●

T2 is then turned on, thanks to the gate current provided by R2

●

T1 is turned on thanks to the gate current provided by T2

Both T1 and the PTC are then ON.

At each zero-current crossing point, the ACST6 turns off. The reapplied voltage across

T1/T2 triggers back T1 which results in some voltage spikes at each zero-current crossing

point (typically around 40 V as shown in Figure 6 for a 230 V compressor).

Applying the click test of norm EN55014, the noise duration could last more than 200 ms

(depending on the type of compressor and PTC). The individual spikes last a few hundreds

of microseconds and are spaced at intervals of 10 ms, so the limits of continuous

disturbance are applicable. Since the spike peaks are less than 100 V, the e-STARTER

solution should fulfill the requirements of EN55014. It should be noted that tests results

greatly depend on the compressor used during the tests.

Figure 5.

e-STARTER schematics