TM 5-3610-286-20 Table 2-3. Reference Designation (cont). Ref des Component n Rectifiers s Solenoid u Electronics Table  2-4.  Electrical  Components. Type Motor  switches Main  three-phase contactor Reference designator a1 a4 a6 a8 a9 a10 a1 3 a1 7 a21 a40 c1 c2 c3 c4 c5 c5a c6 c7 Description Main  switch Motor  protection  switch Motor protection switch Motor  protection  switch Motor  protection  switch Motor  protection  switch Motor  protection  switch Motor  protection  switch Motor protection switch Motor  protection  switch Three-phase  contactor Three-phase  contactor Three-phase  contactor Three-phase  contactor Three-phase  contactor Three-phase  contactor Three-phase  contactor Three-phase  contactor Function On/off  switch  for  electrical equipment Regulating  motor Pile  hoist  motor  feeder Pile  hoist  motor  delivery Compressor Powder spray Suction  brush Sheet  stretching  device Suction  drum Auxiliary pile motor Main  motor,  backward  rotation Main  motor,  forward  rotation Regulating  motor,  fast Regulating  motor,  slow Pile hoist motor, feeder up Safety  contactor,  feeder  pile  hoist Pile hoist motor, feeder down Pile hoist motor, delivery up 2-10