AEMC 1250N Data Sheet

Hand-cranked Megohmmeter Model 1210N (pdf) 12/05 Rev. 03

Technical Assistance [phone] www.aemc.com 1 of 4

The AEMC®Model 1250N is a compact,
self-contained, hand-cranked True
Megohmmeter

®

. This practical and
dependable instrument is designed for
a broad range of plant and field service
applications, such as acceptance
testing and preventive maintenance
of wiring, cables, switchgear and
motors. The easy hand-cranked
operation provides a steady, DC
voltage output across the entire range
for consistently reliable readings. The
Model 1250N has three test voltages
for insulation resistance testing: 250V,
500V and 1000V. Test voltages are
generated in full across the entire
measurement range.

The Model 1250N incorporates a
built-in, sealed alternator and constant
DC voltage circuit to provide a very
stable resistance reading. The

megohmmeter is ruggedly built, with a
safety-yellow cast aluminum case,
aluminum lid and polycarbonate front
panel. The Model 1250N is designed
for harsh, heavy-duty use. An O-ring
seal between the front panel and
case protects the unit against water
and dust. The crank folds against the
unit for storage.

This analog instrument has a unique
auto-ranging feature which expands
the scale ten times: when the pointer
reaches near the end of scale, the
auto-ranging feature activates,
returning the pointer to the beginning
of the scale with the x10 red LED
indicator on.

Insulation resistance is indicated with
a rugged taut-band meter movement
on a logarithmic scale. The indicator

scale is large and easy-to-read,
and has direct-reading on all ranges.
A green LED on the front panel
illuminates when the proper crank
speed is attained, indicating the
presence of the selected output.
The Model 1250N has four terminals
including a guard terminal and
an instrument ground terminal for
user safety.

The Model 1250N is supplied with a
carrying strap with lead pouch, a full
complement of test leads, clips and
test probe to perform any test.

Hand-cranked Megohmmeter
Model 1250N

Hand-cranked Megohmmeter Model 1210N (pdf) 12/05 Rev. 03

Technical Assistance [phone] www.aemc.com 2 of 4

MODEL 1250N

ELECTRICAL

Power Source Hand-cranked, heavy duty brushless alternator and

solid state rectification and amplification

for stable voltage; test voltage reached at 140rpm (approx)

INSULATION TESTS
Test Voltage 250V

11 to 11MΩ; 111 to 500MΩ

(Auto-Ranging) 500V

11 to 11MΩ; 111 to 500MΩ

1000V 10 to 110MΩ; 110 to 5000MΩ

Short Circuit Current 5mA (approx)
Accuracy 2% of Full Scale Length
Automatic Discharge 8s/µF
Charging Time 250V 0.2s/µF

500V 0.5s/µF

1000V 0.5s/µF

MECHANICAL

Scale Direct reading on MΩ and voltage scales; 3" (76mm), black on white
Test Voltage Indicator Green LED indicates proper test voltage and crank speed
Auto-Range Indicator Red LED indicates Auto-Range; multiply MΩ readings x 10
Dielectric Test 2000V, 50/60Hz, between (–), (+), and ground terminals
Meter Movement Rugged taut band suspension
Dimensions 4.7 x 4.7 x 5.1" (120 x 120 x 130mm)
Weight 3.3 lbs (1.5kg)
Case Cast aluminum alloy case and lid painted safety-yellow,

with heavy duty gray polycarbonate front panel;

O-ring seal between front panel and case;

sealed against water and dust; folding crank

Terminals Guard “+” Line (red); “-” earth (black); guard (blue), and ground;

accept standard 4mm banana plugs or spade lugs

SAFETY

Safety Rating EN 61010-1, 600V, Cat. II; 1000V, Cat. I

Double Insulation Yes

CE Mark Yes

Specifications

Features

• True Megohmmeter

®

• Test voltages of 250V, 500V

and 1000V

• Insulation measurements to 5000MΩ

• LED indicates constant voltage

output and proper cranked speed

• Automatic discharge when

measurement is finished

• Auto-Ranging — dual scale operation

for better sensitivity and easier
readings

• Designed for harsh environments:

marine, mining, heavy-duty field,
industrial and military use

• Extra rugged cast aluminum case,

O-ring sealed against rain, water
and dust; aluminum lid

• Compact, self-contained package;

folding crank

• Large direct-reading scale

• Double Insulation

• CE Mark

Applications

• Acceptance testing and preventive

maintenance

• Test motors, cables, switchgears and

electrical wiring installations

• Continuity checks

• Check domestic and industrial

contracting