User Documentation

27 August 2018 Errors and omissions excepted Page 3 of 6
MBS AG D-74429 Sulzbach-Laufen, Eisbachstraße 51; Phone: [phone] / Fax: [phone]
General product description
DACT series differential current transformers are especially sensitive current transformers for logging the smallest AC
currents. In combination with suitable RCM measuring devices, they allow the logging of the smallest sinusoidal
residual currents which escape to earth or through other paths in the event of a fault. In such cases, the measuring
device connected to the differential current transformer analyses the residual current logged by the differential current
transformer, and from this generates corresponding status signals (warning, triggering, or fault messages).
Safety information
The differential current transformers are intended exclusively for logging small AC currents within the nominal current
range specified on the rating plate.
Transformers may be installed or replaced only when the equipment is in a voltage-free state.
Contact with live components is life-threatening. The corresponding upstream circuit-breakers must be removed and
kept safely in such a way that other persons cannot replace them without this being noticed.
Only the intended connection and attachment elements may be used.
The transformers’ secondary circuit is protected by a suppressor diode, integrated into the device, against
overvoltages arising in “open operation”.
Local customary safety and works regulations must be complied with. The transformers must be installed only by
proficient and appropriately trained people.
Liability
The selection of the transformer deployed and of the RCM measuring devices deployed is the sole responsibility of
the user. No liability or warranty is accepted for this. The information in the catalogues and datasheets does not
represent any assurance of specific properties; rather, they result from empirical values and measurements. Liability
for damages which result from operation/project development or malfunctions of the measurement circuitry, is
excluded. The operator/project developer must ensure that incorrect operation, incorrect project development, and
malfunctions cannot cause further damage.
No warranty is accepted for defects and damage resulting from incorrect deployment of the differential current
transformer or from failure to comply with these operating instructions.
Technical data
Insulation coordinates as per DIN EN 60664-1 (version 01/2008)
Rated voltage: 800V
Rated surge voltage: 8 kV/50μs
Degree of contamination: III
DACT measurement transformers
Rated primary differential current (lpr): 25A
Rated secondary differential current: 0.0417A
Rated measuring ratio: 600:1
Rated burden: 100Ω
Rated load: 0.174VA
Frequency range: 42…3kHz
Rated continuous thermal differential current (I
CTH
): 40A
Rated thermal short-term current ( I
TH
): 60 x I
PR
= 1.5kA/1s