Figure 5-8. Testing the galvanometer

TM 9-1300-277

BLASTING CAP BY GRASPINC THE

FIRING WIRE.

(4) Remove shunt.

(5) Hold one cap lead wire to one post

of galvanometer and touch other lead wire to other post.

(6) If cap is satisfactory, galvanometer

needle will deflect slightly less than it did when the

instrument was tested.

(7) Dispose of defective

caps

placing with material being detonated.

WARNING

CARE

MUST

TAKEN

PROTECT BLASTING CAPS FROM

BEING STRUCK OR COMPRESSED

BY OVERBURDEN THAT IS PLACED

THE

MUNITIONS

Figure 5-8. Testing the galvanometer.

EXPLOSIVES BEING READIED FOR

DISPOSAL.

DO NOT PLACE

WARNING

DEFECTIVE CAPS TOO CLOSE TO

HEN UNCOILING CAP LEAD

THE MAIN DETONATING CHARGE.

WIRES, THE CAP WILL NOT BE

HELD DIRECTLY IN THE HAND, BUT

(8) Shunt lead wires of all caps

WILL BE HELD BY THE WIRES

immediately after testing. Wires will remain shunted

APPROXIMATELY 2.5 CENTIMETERS

until connection to firing circuit.

(1 INCH) FROM THE CAP.

c. Firing Wire. The firing wire may be tested on

LEAD

WIRES

WILL

the reel, but must be retested after unreeling as

STRAIGHTENED OUT BY HAND. DO

uncoiling may separate broken wires. Firing wire will be

NOT THROW, WAVE, OR SNAP TO

tested as follows:

LOOSEN COILS.

(1) Separate firing wire at both ends.

(2) Carefully extend cap lead wires to

Touch wires at one end to galvanometer posts. The

maximum length.

needle should not move. If needle moves, there is a

short circuit in firing wire. Locate and repair as required.

(3) Secure cap to prevent movement

by placing in a hole or behind a barricade.

(2) Shunt wires together at one end and

touch those at other end to galvanometer posts. This

WARNING

should cause a wide deflection of needle.

AN INDIVIDUAL REMOVING THE

movement of the needle indicates a break in firing wire.

SHUNT WILL GROUND HIMSELF TO

A slight movement indicates a point of high resistance

PREVENT ACCUMULATED STATIC

which could be caused by several strands of multi-

ELECTRICITY FROM FIRING THE

stranded wire being broken or by wires not being clean.

Locate defect and repair as required.

Change 1

5-8