The 660 series are true linear, bipolar DC power supplies using a fixed diode rectifier to convert AC to DC, and a pass transistor stage to regulate the output to the power supply. They operate as a DC current source and can be operated manually from the front panel or remotely via a ±10 V input. The user can also set current and voltage limits. The bipolar operation of these power supplies provides a smooth transition through zero, eliminating the need for current reversal contactors or relays.
Linear magnet power supplies have several advantages over switch mode power supplies, including smooth field generation that is nearly free from offending electromagnetic signatures. The clean field background allows greater resolution and finer detail in results drawn from data taken during high sensitivity experiments.
Bipolar architecture furthers the idea of clean field generation. The 660 series power supplies maintain tight control over the entire output range, including zero output. This is achieved without reversal contactors or relays, which produce unintended field spikes and other discontinuities. As a result, field hysteresis and other biases are avoided in experimental data.
The front panel displays the current and voltage outputs with 0.1 A and 0.1 V resolution. The current can be controlled via 100% (full-scale) and 1% (fine adjust) ten-turn indexed potentiometers. The voltage limit is also set via potentiometer. The front panel has connectors for external monitoring of both of these signals. There are 4 green LEDs to indicate when the power supply is on, the status of interlocks, and when the unit is ready for operation. Displaying faults for internal and external failures, overheating, overload, and overpower are 9 red LEDs. High speed fault detection for transistors helps avoid cascade output failures. The front panel also includes switches for standby, output start, polarity, and local/remote mode.
The 660 Series can be controlled by the user via any ±10 V input or by a Lake Shore Model 475 gaussmeter. The combination of these power supplies with an electromagnet and Model 475 gaussmeter form a versatile electromagnet field control system. This system is ideally suited for integration into customer-designed magnetic test platforms for applications including magneto-optical studies, magnetic hysteresis studies, in-line annealing, Hall effect studies, susceptibility measurements, spin magnetic resonance demonstrations, and biological studies.