Hobart 120CU20, Operation And Maintenance Manual With Illustrated Parts List

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OM-2228 / Operation and Maintenance Manual
120CU20 / Series 500120 / 400 Hz. Generator Set
October15, 2013
Chapter 3-1
Page 4
(4) Disconnect the two rectifier-to-generator field leads, which are attached to the rectifier mounting
plate with ring terminals.
(5) Take EXERCISE CARE to prevent damage to leads. Remove kinks in the two generator leads
as much as possible before starting removal operation (The exciter armature will be sliding over
these leads.).
e) Exciter Armature Removal.
(1) Removing the Threaded Key with Sling-Hammer Puller
Refer to Figure 2 for location of threaded machine key. Attachment of the assembled puller to the
key in one operation is not recommended because the weight and bulk of the assembly make
threading the 1/4 inch stud into the key rather clumsy. This could result in cross-threading and
damage to key and stud. It is safer and easier to attach as follows:
a Thread stud (1, Figure 3) into adapter (2) until it bottoms, then thread this assembly (1) and
(2) into key until stud bottoms in key threads. Tighten securely.
b If hammer (5) and rod (4) are not already assembled, thread one nut (3) onto adapter end of
rod (4). Thread rod into adapter until it bottoms, then tighten nut securely against adapter.
Slide hammer (5) onto rod and install washer (6) and two nuts (3). Thread nuts onto rod until
both nuts are full threaded and locked together.
WARNING
Be very careful during removal process (slide-hammering) to avoid injury to hands.
CAUTION
Exercise care to prevent breaking or damaging stud.
c Position the hammer at the adapter end of the rod.
d Quickly move hammer to outer end of rod with a rapid, slinging motion. HOLD the hammer
through the entire motion. If the hammer is allowed to slide free on the rod, the stud could be
DAMAGED or BROKEN.
e Repeat step (c) and (d) as required to loosen key, then remove key and slide-hammer puller.
f After key is removed, apply penetrating oil in the armature and shaft keyways.
(2) Removing the Exciter Armature.
CAUTION
Leads may be damaged if armature is turned too far in either direction.
a Place a block bar (pry bar) into the generator fan assembly to keep the generator armature
from rotating.