12226 Simpson, 12226 Datasheet - Page 7

• Manufacturer Part Number: 12226
• Description: Analog Multimeters 270-5 VOM HIGH A
• Manufacturer: Simpson

Specifications of 12226

• Accuracy: +/- 1.75 %
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

5.3
5.4
5.5
a.
b.
c.
d.
The 1 and 2 Amp fuses (also the 1A spare) are located in the externally acces-
sible battery and fuse compartment. Access compartment by de-energizing and
disconnecting the test leads and loosening the single captivated screw on the
compartment cover. To replace or check a fuse, apply pressure to the 1 amp fuse
cup then rotate the plate to expose a selected fuse for removal from the panel’s
cavity.
Replace the 1 and 2 ampere fuse with the specified fuse type only. (See replace-
ment parts list, Table 6-1, for proper fuse type.)
Periodic inspection of the test leads is recommended to detect cuts, burned ar-
eas, deterioration or other damage that could reduce the insulation strength of
the leads.
Before returning the Instrument for service, check the performance and make
sure that the electrical and mechanical configurations have been restored to their
original ratings and condition.
a.
b.
c.
Two batteries are used to supply power for resistance measurements, a 1.5V
D and a 9V battery. When it is no longer possible to adjust the pointer to zero
for the R x 1 and R x 100 ranges (refer to ZERO OHMS ADJUSTMENT
paragraph 4.17) replace the 1.5V battery. When it is no longer possible to
adjust the pointer to zero on the R x 10,000 range, replace the 9V battery.
Recommended replacement batteries are a 1.5V, D size, NEDA 13F and a
9V, NEDA 1604.
To install or replace a battery, de-energize and disconnect test leads from the
Instrument, then remove the cover to the externally accessible battery com-
partment by loosening the single captivated screw.
Observe polarity when replacing the 1.5V D battery and connect as indi-
cated. The D battery is held in place with spring clips which also act as
battery contact clips. The 9V battery contacts and connector are polarized.
To remove the 9V battery, first withdraw battery with mated connector from
the compartment, then remove connector.
Fuse Replacement
Test Lead Inspection
Care
Immediately clean all spilled materials from the Instrument and wipe dry. If
the spillage is corrosive, use a suitable cleaner to neutralize the corrosive
action, and remove the spillage.
When the Instrument is not in use, rotate the function switch to the OFF/
TRANSIT position.
Avoid prolonged exposure or usage in areas subject to temperature and
humidity extremes, vibration or mechanical shock, dust or corrosive fumes,
or strong electrical or electromagnetic fields.
!
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1.
1.1
1.2
The Simpson Volt-Ohm-Milliammeter 270 Series 5 is a rugged, accurate, com-
pact and easy-to-use instrument that will make accurate measurements of AC
and DC voltage, direct current, resistance, decibels, and output voltage. The
output voltage function is used for measuring the AC component of a mixture of
AC and DC voltage. This occurs primarily in amplifier circuits.
New Features for the 270 are:
No single protective device nor even a combination of devices as found in the
270 can fully protect a multipurpose instrument under all overload conditions.
Despite all the built-in-protection provided, however, severe overloads can dam-
age the Instrument when the Instrument is misused. The fuse/varistor combina-
tion in the 270 has been designed to afford maximum instrument protection un-
der foreseeable overload conditions which might occur within the measuring
capabilities of the Instrument. However, the operator must use care to avoid
severe overloads, particularly when working in high voltage circuits.
a.
b.
c.
NOTE: The 0-10A range is not fused. The shunt connects directly to the -10A and
d.
INTRODUCTION
General Description
New connectors between the Instrument and the test leads, eliminating a
shock hazard if a connector is inadvertently pulled out of the Instrument jack.
An OFF/TRANSIT position, which is added to the function switch to protect
the meter movement during transit. (This position shunts the meter move-
ment and opens the internal connections to the COMMON and + jacks.)
A test lead set with molded elbow plugs at one end for connection to the front
panel input terminals and test probes at the other end. The test probes have
a non-slip grip surface and a barrier to maintain the spacing between the
user’s fingers and the probe tip. Threaded shoulders at the probe tip accept
screw-on alligator clips (supplied) or an accessory AC or DC 5000 volt range
extending probes.
Overload Protection
Fuses: Basic overload protection is provided by a small, inexpensive and
easily obtainable 3 AG type, 1 ampere, quick-blow fuse. This fuse is rated to
interrupt circuit voltages up to 250 volts. A supplemental high energy fuse is
provided for additional protection from severe overloads. This fuse is the
Bussman Type BBS 2A 600 V and has an interruption capacity of 10,000
amps AC. The Littlefuse Type BLS 2A 600 V with an interrupt capacity of
100,000 amps AC may also be used.
For maximum protection replace the 1A fuse with a Littlefuse Type 312001
only. This will allow the combination 1A and 2A fuse to give maximum protec-
tion to the unit and user under overload conditions which may occur within
the measuring capability of the VOM.
If the Instrument fails to indicate, the 1 Amp or the 2 Amp fuse may be burned
out. (Refer to paragraph 5.3 for fuse replacement.) A 1 Amp spare fuse is
furnished with each Instrument. Fuses are located in the battery and fuse
compartment.
+10A jacks.
Two diodes connected across the meter movement afford protection to the
movement by circumventing excessive current around the movement in the
event of an overload.
7