In the preferred embodiments switches are electromagnetic relays; other types of switches suitable for the voltages and {HEAD ~ currents} of the motor circuit, or even digital logic, can be employed in {TAIL ~ alternative embodiments} 
In the preferred embodiments switches are electromagnetic relays ; other types of switches suitable for the voltages and { HEAD ~ currents } of the motor circuit , or even digital logic , can be employed in { TAIL ~ alternative embodiments }
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