GenRad 1864-1644 Submarine Cable Test Megohmmeter

  • Ideal unit to test cables on submarines
  • Designed to replace the GenRad 1644
  • Unit has “reverse polarity” to operate like a GR 1644-A, while maintaining the higher performance of the GR 1864
  • Up to 3% Accuracy
  • 200 Test Voltages from 10 V to 1090 VDC
  • 50 kΩ to 200 TΩ Measurement Range
  • Maximum of 5 mA Charge Current
  • Analog Output
  • Suggested Equipment in Boeing Service Bulletins for DC-10, 747 and others
  • Self Contained, Portable Carrying Case
  • Large, Direct Reading Front Panel Meter
  • Reliable High Quality Instrument Designed to Last up to 30 years
Priced at

The 1864-1644 Megohmmeter is the choice for more demanding applications. The test voltage can be set to any value from 10VDC to 109VDC in 1-volt steps and to 1090VDC in 10 volt steps. Thus the GenRad 1864 can be set to any common, or uncommon test voltage for ceramic, mica or paper capacitors, or other devices. The reverse resistance of rectifiers can be readily measured; the low test voltages are especially useful in measuring solid state diodes. An additional range on the 1864-1644 Megohmmeter permits measurements up to 200 TΩ (2 x 1014Ω)

Stability of calibration in the 1864-1644 Megohmmeter is maintained by use of a four-transistor unity gain amplifier.In addition, no warm-up drip is encountered, and high zero stability is maintained during operation.  Human engineering has not been overlooked in the GenRad 1864 Megohmmeter as evidenced by the warning light that is activated by the application of the test voltage. The 1864 employees a Measure/Charge/Discharge switch and provision for performance grounded and ungrounded measurements.

The 1864-1644 Megohmmeter is easy to use with direct-reading meter indication and lighted range switch that shows the multiplier for each range and voltage. The maximum current possible at the terminals is limited to a 5mA and a panel light near the terminals warns when voltage is present.

Stable power supplies and feedback voltmeter circuit minimize drift and time wasting adjustments. Guard and ground terminals permit measurement of grounded or ungrounded two- or three-terminal resistors. The instruments are supplied in a convenient, portable, Flip-Tilt case that is a stand for the meter in use and protects
it in transit and storage

Some GenRad 1864-1644 Megohmmeter Applications

  • Testing Insulation Resistance of Wire and Cables


Resistance Accuracy
: (min reading 0.5) Range 1-5: ± 2(meter reading +1)%
Range 6: ± 2% to accuracy above,
Range 7: ± 3% to accuracy above,
Range 8: ±5% to accuracy above
Voltage Accuracy: (across unknown): ≥ 100 V: ±2% and < 100 V: ±(3% + 0.5V)
Short-Circuit Current: 5mA approximately
Voltage and Resistance Ranges

Voltage  Rmin (Full Scale)  Rmax  Useful Ranges 
10VDC to 50VDC  50 kΩ 2 TΩ 7
50VDC to 100VDC  200 kΩ 20 TΩ 8
100VDC to 500VDC  500 kΩ 20 TΩ  7
500VDC to 1090VDC  5 MΩ 200 TΩ 8