Figure 4-3. Heel Contact Springs - Hitachi PN-150BE Manual

Biased high efficiency vital relay

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Table Of Contents

Table of Contents

4.5.5.1. Heel Contact Springs

a. Original Design

Before adjusting the heel springs it should be determined that dimensions of

0.094" - 0.100" exist as shown in Figure 4-3 for outside to outside across the flats

of the depressions of the heel springs where the slots of the operating arm rest. If

they need adjusting, it must be done by bending the springs at the outer ends.

After this adjustment it must be determined that the free ends of the springs are

pressing against each other and that they are aligned within 1/64 of an inch as

shown in Figure 4-3.

b. Bifurcated Design

Before adjusting these heel springs it should be determined that the dimensions

exist as shown in Figure 4-3 and that the bifurcated parts have a slight trapped

pressure against the main member.

ORIGINAL DESIGN

4.5.5.2. Adjusting Front and Heel Contact Springs

Using the Test No. 2a values per Table 4-1, hold a gage of the proper value firmly at the

main stop pin by energizing the relay, adjust the front contact springs so that light is just

barely visible between the contact tips. A 0.003" thinner spacer should allow the

contacts to close. Deenergize the relay and remove the gauge.

Remove the operating arm by slightly compressing the extreme front end of the heel

spring and hold it clear from all heel springs. Adjust the heel spring members so that

there is from 0.005" to 0.010" clearance between the front contacts and the heel contact

tips.

Replace the operating arm and work the armature by hand a few times to get the

operating arm into its normal position. When replacing the operating arm make certain

that the same side is to the front, as reversing the arm may change adjustments

because of slight warpages and molding tolerances. On later production arms the word

"Front" is molded on one side.

Reinsert the Test No. 2 gauge used above, energize the relay and readjust the front

contact springs as before. Check that the Test No. 2b value allows the contacts to

close.

PN-150BE Biased High Efficiency Vital Relay

.100"

.094"

APPROX .020"

APPROX .016"