KCM161Mx Series
 
 KCM161Mx - INSULATION GUARD FOR NON-GROUNDED AC NETWORKS
  • Direct connection up to 690V line voltage, up to 1,4kV with HV adapter for both single or three phase systems
  • Monitoring during both live and standby conditions
  • Protection against harmful DC voltage exposure
  • "Megger" - safe to 1.4kVDC when aux power is OFF
  • Immune to earth capacitance and voltage surges
  • For use in land, marine, offshore, sub-sea and ocean floor Installations
  • Complies with IMCA D 045 Code of Practice
  • Analogue output proportional to meter reading (F-version)
  • Optional slave indicator
Application
The digitally controlled KCM161Mx series monitors insulation level between a non-grounded (IT) AC mains and its protective earth, regardless of whether the mains is live or non-live (standby) in marine and offshore installations.

IDV MEASURING PRINCIPLE
Insulation is measured between the complete galvanically interconnected AC network and its protective earth. The unit injects a sequentially coded measuring signal to the monitored system. The signal flows to ground via the path of the insulation fault, the level of flow indicates the insulation resistance. The measuring accuracy is not influenced by any normal kind of load attached to the AC network.

An AC or DC auxiliary voltage is required for the unit, if powered from a separate source the network can also be monitored during standby conditions. Only ONE KPM161Mx can be connected to each IT-system. The ohmmeter and the triple-zone status LEDs give at a glance the clear safety message:
  • ALARM
  • WARNING
  • HEALTHY
General
HIGH ENERGY DC VOLTAGE IN YOUR AC MAINS, AN UNKNOWN AND NEGLECTED PROBLEM
Experience has confirmed that full cycle half-wave and partial cycle full-wave rectifier/regulator loads, or a semiconductor failure in heavy power rectifiers/inverters may impose high energy DC voltage on the AC supply line voltages. Intermittent or ENDURING imposed DC voltage is reported to be up to several hundred volts with positive or negative polarity relative to protective earth.

This DC voltage will distort insulation measurements, and may cause breakdown of protective guards The uncontrolled DC energy can cause functional problems by saturating magnetic cores and influence performance of current and voltage transformers, reactors, motors, regenerative drives, generators and regulators.

It is also a fact that this serious malfunction normally remains undetected and unknown to the crew. The M-variant therefore includes a unique DC voltage detection function with an alarm output.

When a "foreign" positive DC voltage exceeding 17V or a negative DC voltage exceeding 3V are detected on the monitored AC supply the DC detection function will within 20 seconds disable the insulation measuring function to avoid false readings, isolate the unit input, activate LED "DC EXPOSURE" and trip relay 3. In this mode unit will sustain continuos high-energy exposure up to +/- 800VDC. The "pathfinder" function identifies polarity of imposed DC. At 10 minutes intervals the unit senses if DC is still present and will reset automatically and restore normal operation when DC exposure ends.

To detect presence of harmful DC voltage connect a voltmeter between any AC supply line voltage and protective earth, and set the meter function switch to AC and DC alternately.

NOTE
The standard Insulation Guards KCM161x and KCM163x are protected against sporadic AC and DC voltage surges imposed on the monitored AC network.

Exposure to enduring  high energy DC voltage (reported to be up to several hundred volts with positive or negative polarity) will instantaneously cause the meter to read false insulation value and may destroy the unit.

OUTPUTS
All F versions have an isolated analogue output proportional to insulation level. If output is used for remote meter reading, we recommend 0-1mA for the slave indicator.

SAFETY
The KCM161Mx range is designed to comply with specification IMCA D 045 "Code of Practice for the Safe Use of Electricity Under Water" issued by IMCA.

The unit meets IEC60092-504 and the relevant environmental and EMC tests specified in IEC60068/60092 and IEC61000/60533 respectively, to comply with the requirements of the major Classification Societies.
 
INTELLIGENT SETTING ASSISTANCE
KCM161Mx has a built-in Assistance tool for setting/verification of the trip levels and the analogue output.

When either the Warning or Alarm potmeter on the front is operated by user, the slave meter goes into Assistance Mode and meter reading and analogue output will reflect the potmeter setting.
 
Reset / Parallelling Disable Function
KCM161Mx has a built-in disable function (available only when DC Aux. Supply is applied). When connecting two or more IT-networks together only one unit can be active, the other(s) must be disabled. When unit is disabled the power led will flash every 2 seconds to indicate that unit is inactive.
 
KCM161M & KCM161MF - KCM161MG & KCM161MGF
Scale range: 0-1000kΩ - ∞ (>6MΩ)
This unit is used for hospital, industrial, marine and offshore installations.

Start of monitoring function is delayed when auxiliary power is switched on (default 5 secs delay). The unit has minimum 150 mS detection time for any insulation fault.

Direct connection up to 690V line voltage. Up to 1,4kV via HV adaptor CH163/1,4.
 
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