Leroy-Somer — Reassembly PLS 355 and PLS 400 motors
Repair & overhaul · Motor assembly
From a Leroy-Somer service manual — check it applies to your exact model before use.
Before you start
- Use a guide wire to pass end shield probe wires back into the terminal box
Procedure
- Heat the fan (7) and fit it on the shaft, then fit the brake nut, lock it and push down the tab
- Rebalance rotor (3) and fan (7) assembly if a new fan has been installed
- Insert the rotor into the stator taking care not to touch the winding
- Fit the inner bearing retainers (33) and (53)
- Fit the new bearings (30) and (50), heated to 100-110°C
- Mount deflectors (35) and (56), then the nuts and brakes, lock them and push down the tabs
- Grease the bearings according to the grease quantity table
- Before fitting shields, screw a threaded rod into a retainer tapped hole to maintain the grease nipple hole position
- Replace shields (5) and (6) with preloading washers or springs (59) held with grease, tighten shield and retainer screws
- Fit the labyrinth seal (257), lock it with its screws and ensure the rotor turns freely
- Fit the shield (5) and (6) strap(s) (114)
- Replace the key (21)
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Bearings heated to 100-110°C
- Grease quantities per table (section 6.6)
Source: Leroy-Somer service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.