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Power supplies for electromagnets

From Lake Shore Cryotronics

The Model 643 and Model 648 power supplies are linear, bipolar current sources with true 4-quadrant characteristics. Both power supply models have been in operation for years in systems such as VSM and Hall effect, but are also available as stand-alone units, e.g. for an existing electromagnet.

The Model 643 can supply a solenoid with a current of up to ±70 A at 35 V and has a resolution of 20 bits (internal programming). The Model 648 delivers up to ±135 A at a voltage of 75 V.

Both models are not only particularly low noise but also impress with high current rates without overshooting. In combination with Lake Shore electromagnets, magnetic field changes of up to 1 T/s are possible.

Features

Compact design
Analogue programming possible (IEEE-48 and RS-232C)
Low noise
Smooth and continuous ramps
Current ramps from 0.1 mA/s to 50 A/s possible
Integrated fault protection

Specifications

Model 643

Type	Bipolar, 4-quadrant, DC current source
Current generation	Fully linear regulation with digital setting and analog control
Current range	±70 A
Compliance voltage (DC)	±35 V nominal

Maximum load resistance	0.6 Ω for ±70 A DC operation at +10% to -5% line voltage
Minimum load resistance	0.4 Ω for ±70 A DC operation at +5% to -10% line voltage
Load inductance range	0 to 1 H
Current ripple	5 mA RMS (0.007%) at 70 A into nominal load
Interfaces	IEEE-488.2, USB
Software support	LabVIEW driver

Model 648

Type	Bipolar, 4-quadrant, DC current source
Current generation	Fully linear regulation with digital setting and analog control
Current range	±135 A
Compliance voltage (DC)	±75 V

Maximum load resistance	0.55 Ω for ±135 A DC operation at +10% to -5% line voltage
Minimum load resistance	0.41 Ω for ±135 A DC operation at +5% to -10% line voltage
Load inductance range	0 to 1 H
Current ripple	10 mA RMS (0.007%) at 135 A into nominal load
Interfaces	IEEE-488.2, USB
Software support	LabVIEW driver