The resistor NTT RD 158 is a water-cooled damping resistor, which is used for traction in railway applications. The resistor is used in series with filter capacitors in the 1.5 kV and 3 kV DC network.
For this purpose, the device must be designed for a high single pulse energy and nominal voltage. The inductance of the resistor contributes to limit the inrush current - here are wirewound resistors the right choice.
The advantage of the resistance unit NTT R D158 is that 4 damping resistors are housed in one unit. This means a compact construction and low cost when connecting the resistor.
REO high-voltage resistors are designed, produced and certified specifically for the railway technology. The specially designed winding technology allows a higher withstand voltage due to the spatial separation of the wires. The use of railway-compatible, high quality materials, together with the complete encapsulation in profile design lead to protection classes up to IP 65.
Maximum energy with minimum space
NTT R D 158 / 2600
0.1 - 1
Values of the single resistors
NTT R D 158 / R1
NTT R D 158 / R2
NTT R D 158 / R3
NTT R D 158 / R3
Higher power ratings on request
The ratings apply for 100% duty cycle and free access and exit of cooling air.
In general: Is the ambient temperature higher than 40 °C, the continuous power must be reduced by 5% per 10 K temperature rise.
NTT R D 158
The power ratings apply for continuous duty. The power ratings can be increased in short-time operation in function of duty cycle by multiplication with the relevant factor from the diagram below or according to the formula as follows.
The resistance values refer to standard products with a standard tolerance of +/- 10% with an ambient temperature of 20 °C. The resistance value insignificantly changes in function of the winding temperature. Therefore, resistance changes of approx. +10% in comparison to the cooled-down conditions may occur.
The aluminum cooling pipes used are suitable for most of the standard cooling liquids and oils. In order to ensure safe operation of the units, it is most important to comply with the VBG-cooling water regulations (VBG-R 455 P). Cooling channels: Aluminum (AlMgSi 0.5) Di = 10.5mm; G1/4” inside thread
Cooling medium: for example, water with anti-corrosion agent for closed cycle cooling system; oils
The cooling pipes are not suitable for industrial and potable water, aggressive liquids, sea-water or de-ionized water. The maximum inlet temperature is + 25 °C and the maximum drain temperature + 45 °C.
The resistors are designed with a flow rate of 10 l/min. This should preferably not be gone below. A lower flow rate may result in a reduction of the power. This is to be checked.