PS Options

Power Supplies - Optional Features

CURRENT REVERSAL - The current reversal option is incorporated into the main power supply enclosure for the purpose of reversing the current polarity automatically at any setting. The current reversal is initiated by the pushbutton switch located on the front panel of the power supply. Depressing the REVERSAL switch will automatically set the output current to zero, reverse polarity, then ramp back up to the previous setting. The electronic circuitry automatically pauses at zero current to allow for the dissipation of any back EMF that may be generated from an inductive load. The reversal time is dependent upon the power supply, load impedance, and current setting.

RELAY CONTROL PACKAGE - This option is used to operate the AC ON, DC ON, DC OFF, and REVERSAL (if so equipped) from a remote source.

BACK BIAS - Power supplies equipped with the back bias option have the capability to overcome a typical residual field that would be found when driving an ironcore electromagnet. This is accomplished by a bias current, opposite in polarity to the normal current output of the supply.

ANALOG OUTPUT - The power supply can be equipped with a current monitor. This output is a 0 to +10 VDC signal that is proportional to the output current where 10 volts is equal to 100% current. This output can source any device with an input impedance greater than 5 kOhm.

REMOTE CONTROL CONSOLE OPTION - A separate, remote control console can be provided in place of the standard panel mounted unit when required. The console measures 3.5"H x 19"W x 18"D. Refer to the power supply control panel description section for details.

IEEE/RS-232 COMMUNICATIONS PORTS - Complete control of any Walker Scientific HS power supply is achieved through either an IEEE488 GPIB parallel interface or an RS-232 serial interface. The RS-232 interface allows complete control with a standard PC RS-232 serial port, eliminating the requirement for any additional PC I/O cards for communicating with the power supply. The IEEE488 GPIB interface permits operation of the power supply on the same interface bus as other GPIB compatible equipment (each device on the bus must be set to a different address). The GPIB address can be set via a dipswitch setting to allow the interface to be controlled independently of other equipment on the same bus. Both interface options enable full computer control of all power supply functions, including power on/off, polarity reversal, and the setting of the output current level with up to 20 bits of resolution (2 ppm). The user can also monitor water coolant flow status (go/no go) and actual output current with up to 16 bits of resolution (15 ppm).

A simple command structure is used to execute each power supply function. The user can write software routines for controlling the power supply or use a commercially available software package such as National Instruments LabVIEW(TM), or we can provide the software support required for your application.

FIELD REGULATION - A universal field control package consisting of a precision gaussmeter, probe and power supply interface provides a system designed to allow full user control of the electromagnet through either current or field regulation.

When operating in the current control mode, the current to the electromagnet is sensed and fed back to the power supply control to maintain a constant current. Current to the electromagnet will remain constant with changing load impedance and over specified line voltage variations of +/-10%.

When the system is operated in the field control mode, the magnetic field in the electromagnet gap is sensed by a Hall effect sensor and gaussmeter. The signal from the gaussmeter is then fed to the power supply control to maintain a constant field in the electromagnet air gap. The field in the electromagnet will remain constant for variations in gap size or with the introduction of other objects into the air gap.

FIELD CONTROL -
Field set accuracy:
   ±0.20% of range with HP-93 probe (10X) (Ranges: 0-10 or 0-100 kilogauss)
   ±0.35% of range with HP-33 probe (1X) (Ranges: 0-1 or 0-10 kilogauss)

Field set resolution: 0.1% of range (0-1 or 0-100 kilogauss)

Field Regulation: ±0.02% or 25 milligauss, whichever is greater.
Max. line voltage variation: ±10%

   Functional Diagram

Ask an Applications Expert about any of these products