T&R DSM600 High Current Micro-Ohmmeter

The T&R DSM600 High Current Micro-Ohmmeter is suitable for measuring very low resistances in a wide range of applications. The DSM600 has a maximum test current of 600A DC and offers a direct Ohms reading at any current. Contact resistances in circuit breakers, switch panels, isolators, and busbar joints are all easily and safely measured. The DSM600 is simple to operate as the user only needs to switch the output on and set the test current. Selection of all ranges is fully automatic and current, voltage and resistance are displayed simultaneously at all times. The resistance is calculated from the test current and sense voltage and there is no need to set an exact test current to guarantee an accurate test result. To assist the user, all readings are held on the display when the output is switched off. Connecting the DSM600 to a PC running the optional DSMlog software adds data capture and reporting functions to the unit, allowing test results to be exported directly to Excel or saved to a file. All results are time stamped, and a comment may be added to each test. Data capture can be controlled from the PC, and the resistance of a test object can be monitored over a period of time. Alternatively, connecting a printer allows all of the test parameters to be printed automatically whenever the reading is held.  For safety purpses the unit is protected by electronic over current and duty cycle trips on the output, thermal trips on the power components and fuses on the input and regulator. An earth terminal is also provided for connection to a local earth.

T and R DSM600 features
► 0-600A DC test current
► 0.1µΩ resolution
► mV, A, and µΩ displayed simultaneously
► Max resistance of 4mΩ at 600A and 400mΩ at 10A
► Direct Ohms reading at any current
► Large back-lit liquid crystal display
► Thermal and over-current protection
► Compact and portable
► Isolated RS232 interface for printer or PC connection
► 90-264V Supply voltage range
► High quality 3m lead set supplied as standard

Example of how to test busbar joint resistance
Testing the joint resistances of a busbar using the DSM600 is a simple task. Before undertaking any testing, always ensure that power to the object under test is off and the object is earthed. The DSM600 should also be earthed. With the output of the DSM600 off, connect the device's output cables to the busbar, ensuring that all joint resistances to be measured are included in the circuit. Connect the sense leads to the first joint to be measured, and switch the output of the DSM600 on. Increase the current to the desired level, and switch the output off. The readings will be held on the display. Move the sense leads to the next joint (shown faded on the diagram), and switch the output of the set on and off to measure the resistance of the joint. The process is even simpler if the optional printer or a PC and DSMlog software is used. In this case the results are printed out or logged to the PC every time the reading is held by pressing the off pushbutton.

► T&R DSM600
► Spare fuse set
► Supply lead
► 3m long output lead set
► Operating manual

Outputs
The full output is available for a 230V supply, a reduced output is available from lower supply voltages. The DSM600 is output rated at 600A for 1 minute, 400A for 5mins and 200A continuously.

Metering
All metering is fully auto-ranging, selecting from two current ranges and three voltage ranges.

► Supply requirements: 90 - 264V AC, 1 phase, 50/60Hz, 3200VA max
► Maximum resistance: 4Ω at 600A, 400mΩ at 10A
► Storage temperature: -20°C to 60°C
► Operating temperature: 0°C to 45°C
► Dimensions: 332 x 288 x 202mm
► Weight: 26.4kg
► Lead set weight: 6kg