Insulation, Residual-Current, Monitors, DoldPCB,Safety,Relays,DoldPCB,Safety,Relays,DoldPCB,Safety,Relays,DoldPCB,Safety,Relays,Dold

Insulation And Residual-Current Monitors

Unscheduled downtimes of machines and plants mean a considerable cost factor. By early detection of insulation faults DOLD insulation monitors help to prevent failures of electrical equipment and thus ensure a better operating reliability and plant safety.

They are used both in earthed and also non-earthed systems, but differ in their function principle:

In earthed systems (TN systems) DOLD differential-current monitors detect fault current with the principle of differential-current measurement and are mainly used to avoid cost-intensive downtimes and to prevent the risk of fire which is latent in the case of slowly evolving insulation faults.

In non-earthed systems (IT systems), the insulation resistance to earth of the system to be monitored is measured. Such systems are secured by insulation monitors the use of them in IT systems is required by law by the norm “Safety of Machinery” DIN EN 60204-1 or DIN VDE 0100-410. Thanks to deliberately kept simple functionality of DOLD’s insulation monitors customers benefit from a considerable cost advantage combined with the high quality standard accustomed from DOLD.

Advantages

...at a glance:

  • Save space thanks to compact design
  • Cost-effective and easy-to-use by kept simple functionality
  • Flexible by extended application range of our insulation monitors for systems up to 500V AC and 1000 Hz, i.e. also application for 400V three-phase systems Monitor DC systems up to 280V without auxiliary voltage
  • Improve efficiency: avoid unscheduled downtimes and data losses
  • Improve operational reliability and safety: monitor also at standstill, no interruption of operation in the case of single-phase-to-earth fault
  • Better fire safety: detect slowly evolving insulation faults, minimize accidental arcs as frequent fire cause, split and separetely monitor systems in fire- and exlosion-prone areas
  • Improve workplace safety: no malfunctions of machinery and systems due to earth faults
  • Save time during maintenance and repair: reduce cost by early detection of insulation faults and well-aimed repair

Technology

Problem: 

Avoid the risk of fire and accidents due to slowly evolving insulation faults: High-resistance faults to exposed conductive parts and to earth are present if the conductive connection of the fault location includes resistances. Overcurrent protective devices do not respond to this.

Solution: 

In their standard variant our products can be used for d.c. systems or pulsating d.c. systems, and a universal-current-sensitive variant is available for mixed systems:
DOLD differential-current monitors

Problem: 

Avoid costly downtimes Get an information lead to ensure high operational reliability between maintenance intervals.



Solution: 

In their standard variant our products can be used for d.c. systems or pulsating d.c. systems, and a universal-current-sensitive variant is available for mixed systems:
DOLD differential-current monitors

 

Function principle of a differential-current monitor

  • All conductors of the feeder to be protected (apart from the protective conductor) are guided through a current transformer.

  •  In a faultless system, the sum of all currents is zero. No voltage is induced in the current transformer.

  •  If fault current flows via earth, the current difference will cause a current in the current transformer. This is evaluated by electronics.

Non-earthed (IT) systems

Problem: 

The norms DIN VDE 0100-410 and DIN EN 60204-1 require the use of an insulation monitor in non-earthed systems.

Our objective is to meet this norm as cost-effective as possible. 

Solution:

DOLD insulation monitors  are available for d.c. and three-phase systems, a.c. systems and mixed systems. Special-purpose products for monitoring medical areas and motors are also available. 

 

Problem: 

Ensure protection against fire and accidents by early detection of earth fault currents and slowly evolving insulation faults, e.g. safeguarding fire- and explosion-prone areas

Solution:

DOLD insulation monitors  are available for d.c. and three-phase systems, a.c. systems and mixed systems.

Problem:

Prevent unscheduled downtimes due to earth faults in medical areas.

Solution:

DOLD insulation monitors  are available for d.c. and three-phase systems, a.c. systems and mixed systems. Our special-purpose products for monitoring medical areas are certified according to the norm DIN VDE 0100-710.

Insulation monitor connection types in IT systems 

Single-phase, with auxiliary voltage:

 Single-phase, without auxiliary voltage:

Three-phase, with auxiliary voltage:

 

Applications

Differential-current and insulation monitors are used for early detection of insulation faults in applications where unscheduled downtimes of machinery would have serious consequences.

They are used in earthed systems for reasons of efficiency and protection against fire and accidents, but they are required by law in non-earthed systems for the same reasons according to DIN VDE 0100-410 and DIN EN 60204-1. Applications include:

  • Wood working industry: fire prevention
  • Chemical industry: prevent the interruption of chemical production processes
  • Automotive: prevent downtime of entire production lines if one partial area fails
  • Food industry: prevent consequential losses, e.g. failure of a cooling plant
  • Medical: prevent the failure of live-saving facilities
  • Data processing: prevent data loss in computer centers, data processing equipment and systems

Moreover, insulation monitors are used to monitor cut off consumers, which are only needed in certain situations, but must then function without problems, flue gas extraction systems in case of a fire, for example.

Residual current monitors for earthed systems VARIMETER RCM
Function
Type of
voltage
Adjustable
measuring
ranges [A]
Relay
contact/
output
Adjustable
operate
delay
Warning
and alarm
indicators
Test
key
clear
key
Broken
conductor
detection
Housing Style:
Width [mm]
Type
Residual current monitor,
Type A
AC; DC
pulsating
0.01 ... 10;
0.01 ... 30
+
+
LED
+
+
+
Distribution board: 35
Switch cabinet: 35
Residual current monitor,
Type A, with integrated transformer
AC; DC pulsating
0.01 ... 10;
0.01 ... 30
+
+
LED
+
+
+
Distribution board: 105
Residual current monitor,
Type B
AC; DC; DC
pulsating
0.01 ... 3
+
+
LED
+
+
+
Distribution board: 70

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