Miller Electric S-21E Technical Manual page 8

Hub
Wire
• Spring
Retaining
Ring
• OPTIONAL
It is necessary to install the required drive rolls when set-
ting up this unit and also when changing wire sizes.
Base drive rollselection on the following
IMPORTANT:
recommendations:
The dual-grooved drive roll provided with the feeder ac-
commodates.023 through .045 in. (0.6 through 1.1 mm)
wire. This drive roll has both a
knurled groove. Use the "V" groove for feeding .023 and
.030 in. (0.6 and 0.76 mm) wire. Use the "V" knurled
groove for feeding .035 and .045 in. (0.89 and 1.1 mm)
wire. The wire size for each groove is stamped on the
side of the drive roll. When the drive roll is installed in the
feeder, the wire size stamp for the unused groove will be
visible.
The 50 Series wire feeder style drive rolls may be used
with this feeder, but, due to the flat idler pressure roll
used, a knurled drive roll is recommended when feeding
.035 and .045 (.089 and 1.1 mm) wire.
A
WARNING: ELECTRIC SHOCK can kill.
Do not store metallic objects in this compart-
ment. The motor drive assembly is electri-
cally hot whenever the welding circuit is ener-
gized.
TM-1571 Page 4
9
Ret. 50497
Figure 4-1. Wire Feeder Components
"'I"
groove and a
Loose metal objects in this compartment may
create an electrical path between the weld out-
put circuit and any metal surfaces or compo-
nents resulting in electric shock.
IMPORTANT:
can be reversed for reuse when they become worn. Re-
verse rolls to position unused groove(s) to feed wire.
The dual-grooveddrive rollpro vided with this feedercan
"'I"
be reversed, but only to feed a different size wire.
1. Unlatch and open left case access door.
2. Loosen pressure adjustment knob, and pivot
knob free of pressure arm.
3. Pivot pressure arm away to expose drive roll
carrier.
4. For dual-grooved roll supplied with feeder:
a. Choose the proper groove.
b. Slide drive roll onto drive roll mounting hub with
chosen groove toward inside of machine. The
wire size for the unused groove will be visible
after installation.
c. Align the drive roll with holes.
d. Insert securing screws, and tighten.
Pressure Roll
Assembly
(Shown In Open
PosItion)
Both types of 50 Series style drive rolls
GunlFeeder
connector
Securing Knob
Ref. SB-125 923
5-21E