3.  Motors—direct current motors draw several times  their rated current during starting, and magnetic  energy stored in their armature and field coils is  released when the control switch is opened. Figure 4-118  is typical of those tables available for selecting  the proper nominal switch rating when the continuous load  current is known. This selection is essentially a derating to  obtain reasonable switch efficiency and service life. Hazardous errors in switch operation can be avoided by  logical and consistent installation. Two position on-off  switches should be mounted so that the on position is reached  by an upward or forward movement of the toggle. When the  switch controls movable aircraft elements, such as landing  gear or flaps, the toggle should move in the same direction  as the desired motion. Inadvertent operation of a switch can  be prevented by mounting a suitable guard over the switch. Relays are used as switching devices in which a weight  reduction can be achieved or electrical controls can be  simplified. A relay is an electrically operated switch and  is therefore subject to dropout under low system voltage  conditions. The previous discussion of switch ratings is  generally applicable to relay contact ratings. Relays 4-69 Figure 4-118. Switch derating factors. Lamp Inductive (Relay-Solenoid) Resistive (Heater) Motor Lamp Inductive (Relay-Solenoid) Resistive (Heater) Motor 8 4 2 3 5 2 1 2 24 VDC 24 VDC 24 VDC 24 VDC 12 VDC 12 VDC 12 VDC 12 VDC Nominal System  Voltage Type of  Load Derating  Factor