ABB REG316 4 Series - Calibration of the Ancillary Unit Type YWX111-11;-21

REG 316*4 1MRB520049-Uen / Rev. B ABB Switzerland Ltd
4-17
4.2.3.5.2. Calibration of the ancillary unit Type YWX111-11/-21
The measuring bridge of which the YWX111-11/-21 is part must
be balanced with the unit connected by appropriately selecting
the values of the capacitors C
X
.
Fig. 4.5 Calibration of the YWX111-11/-21
Calibration capacitor C
X
: Polyester, ³ 400 V
Calibration can be carried out while the machine is stationary.
Procedure:
· Interrupt the REG 316*4 tripping circuits.
· Connect an AC voltmeter to terminals 1 and 2 of
YWX111-11/-21.
· Connect a decade capacitor in place of C
X
.
· Close the excitation switch.
· Switch on the auxiliary supply U
SH
.
· Vary C
X
until the output voltage across terminals 1 and 2 of
YWX111-11/-21 becomes a minimum; typically
£ 50 mV
r.m.s.
.
Note: It is possible that the 50 mV
r.m.s.
will not be reached in
the case of schemes with shaft filters and increased
YWX111-11/-21 sensitivity (R9 = 1 k
W).