| 摘要 |
circuits for controlling electric power for loads such as fluorescent illumination systems. SUBSTANCE: winding has positive end joined with positive conductor and having tap in predetermined position for supplying selected voltage to selected terminal. First relay contact may electrically connect neutral end of winding with neutral conductor for feeding one of selected voltages, or second relay contact may electrically connect predetermined number of turns of winding according to desired second selected voltage. At short circuiting third relay contact may electrically connect neutral end of winding in above mentioned position for switching system to trouble-proof state in order to prevent formation of open circuit by turns of winding. EFFECT: enhanced reliability and safety of system. 17 cl, 5 dwg
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