Fluke 540B - Page 25

76 pages

Save Page as PDF

To Next Page

To Next Page

To Previous Page

To Previous Page

Loading...

540B

S

TEP

CONT ROL

PO

SITION

OPERATION

a SENSITIVITY LOW

Tap

the

GALV s

witch

against

the

sprin

g

tension

to

POWER

ON

MOMENTARY

just

long

enough

to

see

if

the

GAL-

GALV

VANOMETER

needle

will

stay

on

scale

while

ad

-

REFERENCE

COARSE

justi

ng

the

COARSE

and

MEDIUM

REFERENCE

ADJUST

MEDI

UM

ADJUST

controls

.

Rep

eat

until

a

zero

reading

is

obtained

.

b

GALV

OPE

N

Adjust

the

GALV ZERO

control

for

zero

reading

SENSITIVITY

MED on

the

GALVANOMETER.

GALVZERO

c GALV

LOCK

Usin

g

the

MEDIUM

and

FINE

REFERENCE

REFERENCE

MEDIUM

ADJUST

controls,

zero

the

GALVANOMETER

ADJ

UST

FINE

needle.

d GALV

OPE

N

Adjust

the

GA

LV ZERO

control

for

zero

reading

SENSITIVITY

HI

GH

on

the

GALVANOMETER

GALVZERO

e GALV

LOCK

Usin

g

the

FINE

REFERENCE

ADJUSI'

controls,

REFERENCE

zero

the

GALVANOMETER.

Do not

use

the

ADJ

UST

FINE

REFERENC

E ADJUST

controls

e

xcept

to

null

the

ac

being

me

as

u

re

d.

f GALV

OP

EN

Disconnect

the

external

converter

from

the

ac

being

measured

and

connect

it

to

the

de

standard

source,

being

careful

not

to

exceed

the

rated

value

of

the

external

converter.

Adjust

the

de

source

to

the

approxima

te

rms

value

of

the

acto

be

measured

.

g SENSIT IVI

TY

LO

W

Tap

the

GAL V s

witch

against

th

e

spring

tension

to

GALV

MOMENTARY

just

lon

g enough

to

see

if

the

GAL-

VANOMETER

needle

will

stay

on

scale,

while

ad

-

justing

t

he

de

source

voltage.

Repeat

until

a

zero

reading

is

obtained.

h SENSI

TI

VI

T Y MED

HIGH

Further

refin

e

the

adjustment

of

the

de

source

to

GALV LOCK

maintain

a

zero

r

eading

on

the

GALVANOMETER

in

the

MED

an

d HIGH SENSITIVITY

positions.

i GALV OP EN

Disconnect

the

external

converter

from

the

de

source

and

reconnec

t

it

to

the

ac

being

measured.

j

GALV L

OC

K

Zero

the

GALVANOMETER

with

the

FINE

control.

REFE

RENCE

ADJUST FINE

k GALV

OPE

N

Disconnect

the

external

convert

e r

from

the

ac

being

measured

and

connect

it

to

the

de

source.

1

GALV LOCK

Refine

the

adjustmen

t of

the

de

source

to

obtain

a

zero

reading

on

the

GALVANOMETER. (note level)

m

Repeat

st

eps i

through

1 at l

ea

st

t

hree

tim

es

or

until

repea

tibili

ty

is

attained.

Re

cord

the

de

level

n

Reverse

the

polarity

of

th

e

de

source

and

rep

e

at

steps

i

th

r ough 1

at

least

three

times

or

until

repeatibility

is

attained

.

Record

the

de

level

.

0

The

rms

value

of

the

unknown

ac

volt

age

is

equal

to

the

average

of

the

two

de

voltages

recorded

in

steps

m

and

n.

Figu

re

2-

11.

MEASU

RING

AN UNKNOWN

HF

VO LT

AGE

2- 13

Table of Contents