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10. Move the vane shaft forward and up until the upper back contact heel springs
(No. 4 and 5 can be pushed in back of the shaft). Note: The operating arms
must be held clear of the heel springs.
11. Rotate the counterweight stud toward the contacts and slide the hub out between
the heel springs and the roller stop guide. Note: This will require a slight
deflection of the upper front heel contact springs. The crank pins and contact
operating arms can then be removed after the vane is out of the relay.
3.7.3. Vane Installation
Vane installation is accomplished generally in the reverse order of disassembly. Do not
overtighten or force parts. The following subsections provide additional instructions to
be followed during reassembly. Upon completion of reassembly, calibrate the relay as
directed in Section 3.2.
3.7.3.1. Installing Vane Assembly
1. Check the pivots and trunnion bearings for excessive wear. Clean them with a
dry, lintless cloth and treat them with lubricant J041099 before installing the
vane.
2. Assemble the contact operating arms and crank pins on the vane cranks first.
3. Insert the vane. At least one of the trunnion screw lock nuts should be started
on the trunnion screws in advance, but it may be found necessary to slide the
other nut on one end of the vane shaft in order to bring it into position.
4. Tighten the trunnion screws carefully so as not to damage the pivots. These
screws should be adjusted to center the vane in the air gap and to provide 0.010"
to 0.016" endplay of the vane shaft. With the endplay taken up on each side,
rotate the vane and inspect to ensure that the minimum clearance from the vane
to the pole face is 0.012". If the vane clearance is less than 0.012" reset the
endplay and recheck the clearance. After the endplay has been set tighten the
trunnion lock nuts.
5. Adjust the stroke of the vane by adjusting the roller stop brackets to permit
maximum travel of the vane. In either extreme position of the vane, as permitted
by the roller stops (rollers at the top of the slot), the buffer clips on the vane
should be 3/32 inch from the cores. This adjustment allows maximum travel of
the vane and prevents the buffer clips from becoming wedged in the air gap.
6. Check that the heads of the crank pins have at least 1/16" clearance from the
lock nuts on the trunnion screws when the pin and vane shaft are shifted to
make this clearance minimum. Check that the crank pins are securely locked at
the split ends so that this clearance cannot be reduced.
Copyright 2019
SM 4574F, Rev. 4, March 2019
PV-250 Track Relay
3-11
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