Operating instructions

Operation SW 5250A•SW 3500A•SW 1750A

3-6 Operation Manual

Reference Section 3.4,

Front Panel Programming Conventions

There is only one frequency setting for all three phases. Changing the frequency

of one phase changes the frequency for all phases.

***

The SW can accept only positive numbers when programming phase angle

offset. Because phase angle offset represents a phase lead with respect to the

internal reference, the formula below should be used for a selected phase to

represent phase angle in terms of phase lag:

Desired Phase Angle Lag = 360° – (Ph.B

Angle – Ph.A

Angle)

The examples below are for a two–phase quadrature system:

•

For phase angles Ph.A = 0°, Ph.B = 270°, phase lag would be 90°.

90° = 360° – (270° – 0°)

•

For phase angles Ph.A = 45°, Ph.B = 120°, phase lag would be 285°.

285° = 360° – (120° – 45°)

****

To operate the SW as a DC supply, select the function as “DC+” or “DC-” for

positive and negative DC. “AC+DC Coupling” must also be selected from the

INSTRUMENT menu. The AMPL field is programmed to 0V as a precaution

when changing to or from the “DC+” or “DC-” function.

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For two- or three-phase systems, individual programming fields of amplitude, current

limit, phase angle, and function may be “locked” so that any change made to phase A

will be made to phases B and C. The Lock function is intended for front panel

operation. When using GPIB, use the SOURCE0 command.

To lock a field:

1. Move the field select cursor to the field to be locked in the Phase A Program

menu.

2. Press the

function key. The “¥” symbol should appear to the right of the field

indicating the lock mode is active.

3. Enter the value to be locked into the field.

 The lock will not be active until a value is entered; previously entered

values are not locked.

To unlock a field:

1. Move the field select cursor to the locked field in the Phase A Program menu.

2. Press the

function key. The “¥” symbol should disappear.