Dc Current Measurement - Digimaster DM38A Manual De Empleo

C. DC Current Mea sure ment
Warning – Nev er at te mpt an in-circuit current me asure m ent wh ere the ope n circuit voltag e betw een
ter minals and round is greater than 6 0V D C or 30 V rms.
If the fus e burn s ou t during measurem ent, the Me ter may be da mag ed or the operator himself ma y be
hurt. Dis connect po wer supply b efor e m aking me asur e men t. Use proper ter min als, function, and
range for the m ea sure men t. W hen the te sting lea ds are con ne cted to the curren t ter minals, do not
parallel the m a cros s an y circui t.
To measu re c urr ent, d o th e f ollo wi ng:
11. Tur n off power t o the ci rcuit. Disc harg e al l hi gh-v oltag e ca pacit ors.
12. Insert t he re d t est le a d i nto t he m A o r 20 A or 1 0 A t ermin al and t he bl ack test le ad int o th e C OM terminal. W h en
meas ur in g curr e nt at 200 mA bel o w, ins ert the r ed test le ad i nto m A t ermi nal whi le m eas uri ng cu rrent 2 00mA o r
abov e, insert th e red test l ea d int o 1 0 A or 20 A t ermin al.
13. Set the rotary switch to a n a ppr o pri ate m eas ur em ent p ositi on i n A
14. Break th e cu rrent path t o be teste d. Conn ect the red test l ea d to th e m or e positiv e sid e of the b re ak a nd t he bl ack
test lea d to th e more ne gativ e sid e of the br eak.
15. Tur n on power t o the ci rcuit.
The measur ed v alue sho ws on th e dis pl ay .
Note
If the v alue of current to b e me as ured is u nkn o wn, us e th e maxi mum me asur em ent p ositi on ( 20 A) an d 20 A
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termi na l or ( 10A) an d 10 A te rmi nal, and re duc e th e ra ng e ste p by step until a s atisf actory read ing is o btai ne d.
Rep lace appr opri ate r atin g f use when th e fuse is burnt.
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Fuse specif icatio n: 0.31 5A. 2 50V fast ty pe f use , Ø 5 x 2 0 mm.
DM3 9A/ – At 10 A R ang e: For c onti nu ous me asu reme nt < 10 sec onds and i nte rv al not less tha n 1 5 mi nutes.
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DM3 9B– At 2 0A Ra nge: Fo r co ntinuo us measur ement < 10 s eco nds and int erval not less than 15 min utes.
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When cu rrent m eas urement has bee n compl ete d, disco n nect the con nectio n bet we en th e testin g le a ds and the
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circuit u n der t est.
black
(figure 4)
. rang e.
red