Repairs And Replacement; Disassembly; Reassembly; General Parts Replacement - Hitachi PN-150BE Manual

4.4. REPAIRS AND REPLACEMENT

Since the contacts are the wearing parts in this relay, in most cases the relay can be
restored to proper operation by dressing (Section 4.2.2.2) and readjusting (Section
4.5.5) them.

4.4.1. Disassembly

Dismantle the relay only to the degree necessary to complete repairs. Refer to Section
5 for part information and location of parts. In general, to dismantle the plug-in relay,
proceed with the following sequence:
1. Remove relay cover seal.
2. Carefully remove plastic cover.
3. Remove/disassemble relay components as required.
4. Remove contacts/contact block as required.
5. Remove permanent magnet as required.
These magnets are of a special alloy that permits retention
of proper strength indefinitely if not abused. When not in
place on relays, magnet assemblies should be kept
separated from other magnetic objects, and the screws,
which hold the extension to the magnet be kept tight. Should
a magnet become weakened, it should be returned to the
factory for recharging by the special equipment required to
fully charge the magnet. It will then be aged to its best
working strength.

4.4.2. Reassembly

Reassembly is accomplished generally in the reverse order of disassembly. The
following paragraphs provide additional instructions to be followed during reassembly of
this relay.

4.4.3. General Parts Replacement

Do not overtighten or force parts when reassembling a relay. Upon completion of
reassembly, calibrate the relay as directed in paragraph 4.6.
4.4.3.1. Replacing Contact Block
If the contact block is to be replaced by another, remove the old block, then use a small
punch to remove the small dowel pins. Attach the new block with the four screws.
Torque the contact block screws to 10-inch pounds. Run a #42 drill (0.0935 Dia.) thru
the dowel pin holes into the epoxy contact block for a total depth of 9/16" + 1/32 - 0.
Copyright 2019
PN-150BE Biased High Efficiency Vital Relay
NOTE
NOTE
SM 4551L, Rev. 0 1, March 2019 4-6