Yale MPB040E Manual page 109

0620 YRM 0294
1. BRUSH HOLDER (4)
2. BRUSH MOUNTING PLATE
3. BRUSH SPRING (4)
4. BRUSH SET
Figure 4. Brush Assembly
7. Connect new brush wire to its terminal mount.
NOTE: When new brushes must be installed, a rec-
ommendation is to also install new brush springs.
Damage from heat can cause the brush springs to
have the wrong spring pressure.
8. Check brush springs for damage from heat and
corrosion. If brush springs are damaged, install
new brush springs. Check brush springs for ap-
proximately equal pressure.
Brush springs normally have a spring pressure of
approximately:
1.0 to 2.0 Newtons per each cm
(1.5 to 3.0 lbf per each in
with a spring scale.
A brush for a traction motor has an area of approxi-
mately:
5.33 × 1.27 cm = 6.8 cm
(2.1 × 0.5 in. = 1.05 in
Brush springs for the traction motor normally have
a spring force of approximately:
9.1 to 11.3 Newtons
(36 to 44 ozf) when measured with a spring
scale as shown in Figure 5.
NOTE: SOME MOTORS HAVE SPRINGS AS
SHOWN IN FIGURE 7 AND FIGURE 11. SOME
SPRINGS ARE IN PAIRS AT EACH BRUSH
HOLDER.
1. SPRING SCALE
2. BRUSH IN BRUSH
HOLDER
Figure 5. Brush Spring Pressure Check
Brush Replacement
2
2
) when measured
2
2
).
3. COMMUTATOR
4. BRUSH SPRING
11