Snubber Resistors; Testing Snubber Resistors - Allen-Bradley PowerFlex 7000 User Manual

Medium voltage ac drive air-cooled (‘a’ frame) – forge control
Hide thumbs Also See for PowerFlex 7000:
Table of Contents

Advertisement

4-18
Component Definition and Maintenance

Snubber Resistors

7000A-UM151E-EN-P - October 2018
Snubber resistors are connected in series with the snubber capacitors.
Together they form a simple RC snubber that is connected across each
thyristor (SGCT). The purpose of the snubber circuit is to reduce the
voltage stress (dv/dt and peak) on the thyristors and to reduce the
switching losses. The snubber resistors are connected as sets of various
wire-wound resistors connected in parallel. The number of resistors in
parallel depends on the type of the thyristor and the configuration and
frame size of the drive.

Testing Snubber Resistors

Access to the snubber resistor is not required to test its resistance.
Located within the PowerCage under the heatsink is a snubber circuit test
point. For each device, there is one test point.
Figure 4.14 – Testing the Snubber Resistor
Measure resistance between
heatsink and test point.
Snubber resistor test point
7000 "A" Frame

Advertisement

Table of Contents
loading

Table of Contents