The CSU600A and CSU600AT current supply units are high current supply units that have two main fields of application. The first is to conduct primary tests on protective relays. A primary test shows whether all parts of the protection system are functioning together properly within the specified time limits under operating conditions. The second field of application involves conducting current tests on low voltage circuit breakers and overcurrent devices.


The CSU600A is a compact instrument which, together with Timer TM200 and an external ammeter, meets stringent requirements for accuracy, easy handling, and performance. This current supply unit is ideal for:

  • performance and turn-ratio tests of current transformers
  • primary tests of protective relays
  • current tests on low and high voltage circuit breakers
  • commissioning tests that require variable currents

The CSU600AT provides a more comprehensive solution. It has a built-in timer and an analogue ammeter that provide rough current settings quickly and easily. As a result, connection time has been reduced to the bare minimum.


Both the CSU600A and CSU600AT current supply units have an excellent weight-to-performance ratio.

Measurement section

Output for external ammeter: 600/6 A

Inaccuracy: ±0.5%


Timer (only CSU600AT)

Range: 0-999.999 s

Resolution: 1 ms

Inaccuracy: ±0.02% of shown value + 0 to 2 ms

Other: Output for starting external timer


Outputs, AC, intermittent output (CAT I)

115 V mains voltage 

Current | Load time | Minimum output voltage

0 A | Cont. | 6.0 V 

75 A | – | – 

100 A | Cont 5.6 V 

200 A | 15 min | 5.3 V 

300 A | 1.5 min | 4.9 V 

400 A | 1 min | 4.6 V 

500 A | 20 s | 4.2 V 

600 A | 15 s | 3.9 V 


230 V mains voltage

Current | Load time | Minimum output voltage

0 A | Cont. | 9.5 V

75 A | Cont. | 9.3 V

|100 A  1 h | 9.0 V

200 A | 5 min | 8.5 V

300 A | 2 min | 8.0 V

400 A | 1 min | 7.5 V

500 A | 30 s | 7.0 V

600 A | 20 s | 6.5 V


CSU600A/AT datasheet


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