====== Motor ======

^ System | [[parts:drivetrain:start|Motor and drivetrain]] |
^ Handbook item | 52 |
^ Sinclair part no. | C5674 357 |
^ Hoover factory no. | 100431 |

<WRAP tip>This page is a starting point built from the original documents. More detail will be added.</WRAP>

===== Description =====
12 V permanent-magnet DC motor, 250 W continuous, 4,100 rpm, made by Polymotor Italiana (Philips group); derived from a truck cooling-fan motor, not a washing-machine motor. Draws about 3 A free-running, 15 A on the level, 50 A on a 1-in-15 hill, 140 A stalled. 30 A is the maximum continuous current without a damaging temperature rise. Protected by the [[parts:electrics:heat_sensor|heat sensor]], the [[parts:electrics:thermal_trip|thermal trip]] and the control box stall detector. Early end mouldings were brown and brittle; later ones pale.

===== Removal and fitting =====
Stripping the motor and gearbox, summarised from the Unofficial Service Manual.

  - **Lift the brush gear first**, or it will be damaged when the armature comes out. The black brush holders are locked in with a sprag and won't come out easily. The brushes, though, sit in metal sleeves that can be **pulled out of the holders** with steady force. One way is to clamp the wire/holder junction (under the heat-shrink) in a vice and pull the motor away. Don't pull them fully out; keep their orientation.
  - Unscrew and remove the **two through-bolts**.
  - Tap the exposed shaft end (brush-gear end) with a **wooden mallet**. This pushes the plastic sleeve partly off the magnet housing.
  - Pull the plastic assembly clear. The armature comes out with it.
  - **Watch for the two spacers** between the brush-end bearing and the housing. They tend to flip up and stick to the magnets.
  - Pull the armature out of the gearbox steadily. Its end bearings pull out of the gearbox housing.
  - To separate the gearbox from the plastic fingers, use **shims** to open each finger latch at once. The gearbox is a snap fit and is hard to remove unless every latch is released together. The whole epicyclic stage can then be pulled off.
  - A damaged armature/commutator can be **skimmed in a lathe**. Bear in mind the original was **diamond-turned** to a very fine finish to keep brush wear down.
  - **Lubricate the gearbox.** The manual recommends **Castrol LMB** grease (a lithium multipurpose grease).
  - **Reassembly:** fit the two spacers into the end cap, **crinkle washer first, then the plain one**. Push them home with a wooden rod and keep the end cap facing down so they can't fall onto the magnets. Guide the armature in and centre its bearing by poking through the end cap with a suitable tool; when it's centred it drops in cleanly. The end cap and the plastic assembly both have locating features for the magnet sleeve, so line those up.

===== Repairs, replacements and reproductions =====
==== Original part, then and now ====
^ Source ^ Date ^ Price ^
| ESG (Ellar Surplus Goods), Liverpool | Dec 1991 | £106.74 + VAT |
| MATCH, Rotterdam | 17 Jan 1991 | ƒ650,- excl. BTW |
| MATCH-AURORA, Numansdorp | early 1990s | ƒ442,- (motor and gearbox) |

===== Related parts =====
[[parts:drivetrain:motor_brushes|Motor brushes]] · [[parts:drivetrain:drive_gear|Drive gear]] · [[parts:drivetrain:rear_axle|Rear axle]]

===== Sources =====
  * [[docs:owners_handbook|Sinclair C5 Owner's Handbook]] (1985), pp. 30–32
  * [[docs:esg_price_list_1991|ESG parts and price list, December 1991]]
  * [[docs:match_price_list_1991|MATCH parts price list, January 1991]]
  * [[docs:match_aurora_order_form|MATCH-AURORA order form]]
  * Further detail drawn from the [[docs:unofficial_service_manual|Unofficial Service Manual]], the [[docs:hoover_service_engineer_training_notes|Hoover service engineer training notes]] and the [[docs:hoover_assembly_sheets|Hoover assembly sheets]] where relevant