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Introduction
This article describes the installation of linear and rotary motion transducers to circuit breakers. The motion measurement of the circuit breaker’s movable parts is available on the following DV Power Circuit Breaker Analyzers and Timers: CAT34, CAT35, CAT36, CAT64, CAT64A, CAT65, CAT66, CAT124A, CAT125, and CAT126 (in the further text referred to as “CAT”).
CAT devices support both linear (analog) and rotary (digital) transducers:
- CAT34 and CAT64 have one transducer input
- CAT35, CAT36, CAT64A, CAT65, CAT124A, CAT125, and CAT126 have three transducer inputs.
Implementation of CAT and motion transducers provides an assessment of the complete circuit breaker’s operating mechanism and mechanical linkage.
The following parameters can be obtained:
- average velocity (which is calculated based on the main contact’s defined travel distance over a period)
- total travel
- over-travel
- rebound
- contact wipe
- damping time and distance, etc.
These results can be compared to the manufacturer’s reference data and information acquired by previous measurements. This provides indications about the potential wear of the circuit breaker’s movable parts.
Linear Motion Transducers Installation
DV Power recommends the following sets of linear (analog) transducers with different strokes and cable lengths:
| Article | Article number |
| Linear Analog Transducer 150 mm with 5 m connection cable | LAT-150-C305 |
| Linear Analog Transducer 150 mm with 10 m connection cable | LAT-150-C310 |
| Linear Analog Transducer 225 mm with 5 m connection cable | LAT-225-C305 |
| Linear Analog Transducer 225 mm with 10 m connection cable | LAT-225-C310 |
| Linear Analog Transducer 300 mm with 5 m connection cable | LAT-300-C305 |
| Linear Analog Transducer 300 mm with 10 m connection cable | LAT-300-C310 |
| Linear Analog Transducer 500 mm with 5 m connection cable | LAT-500-C305 |
| Linear Analog Transducer 500 mm with 10 m connection cable | LAT-500-C310 |
Table 1: Linear (analog) transducers
Example 1
The linear analog transducer installed on a Mitsubishi SF6 138 kV circuit breaker, model 120-SFMP-40HE, is shown in Figure 2. The transducer moving rod is connected to the lever of the rotating shaft which moves the insulating rod of the main contacts.
The installation was made by using the transducer mounting kit that includes 2x articulated arms, 2x big clamping base, and 2x small clamping base.
Example 2
The linear analog transducer installed on GE 72.5 kV circuit breaker, model DT1-72.5 FK F1, is shown in Figure 3. The transducer moving rod is connected to the horizontal linkage shaft which moves the main contacts of all three poles
The installation was also made by using the transducer mounting kit that includes 2x articulated arms, 2x big clamping base, and 2x small clamping base.
Example 3
The linear transducer with its flexible articulated arm is installed on a static area of the circuit breaker’s housing, as shown below (Figure 4).
The transducer’s movable rod is connected to the lever of the rotating shaft driven by the horizontal movable linkage of the circuit breaker (Siemens 123 kV CB, Type 3AP1F) as shown in Figures 4 and 5.
Rotary Motion Transducers Installation
DV Power recommends the following sets of rotary (digital) transducers with different cable lengths and with corresponding accessories:
| Article | Article number |
| Digital rotary transducer with 5 m connection cable | DRT-250-C605 |
| Digital rotary transducer with 10 m connection cable | DRT-250-C610 |
| Digital rotary transducer 5 m with accessories | DRT-SET-0005 |
| Digital rotary transducer 10 m with accessories | DRT-SET-0010 |
Example 4
Figure 7 illustrates how to install a rotary transducer to a lever of the pole’s main rotating shaft (marked with a red rectangle). The rotary transducer shaft is connected to the rotating lever threaded hole over the flexible coupling and screw-on adapter (matching shaft), as shown in the right part of the figure.
The flexible coupling (marked with a black rectangle in Figure 7 compensates for any small misalignment between the adapter (matching shaft) and the rotary transducer. Complete installation and fixing of the rotary transducer using articulated arms on the crankcase of the circuit breaker pole are shown in Figure 8.
Example 5
Installation of the rotary (digital) transducer in Siemens 245 kV CB (model 3AP1 FI) via universal adapter (shown in Figure 9) for rotary transducer mounting is shown in Figure 10. The universal adapter is installed on the main rotating shaft of the circuit breaker since on the universal adapter there are holes that match with two threaded holes on the lever of the circuit breaker rotating shaft. Finally, the rotary transducer shaft is connected to the universal adapter threaded hole over the flexible coupling and screw-on adapter (matching shaft).
Example 6
Accessories for Rotary and Linear Motion Transducers Installations
All mounting kit components have a robust, heavy-duty design in order to guarantee immobilization and minimize vibrations of the transducers (Figure 13).
In case vibrations are still strong, an additional articulated arm can be mounted (Figure 13a). This will further support the first transducer and additionally reduce vibrations.
During circuit breaker testing, a flexible kit is needed. It can be used on several circuit breaker types providing the required accuracy.
A universal adapter for rotary transducer mounting (Figure 13b) gives the ability to mount the rotary transducer on the different types of circuit breakers.
DV power instruments support products from other manufacturers of test equipment. One of them is the Doble transducer adapter (shown in Figure 14). It can be used to interface any Doble travel transducer with a DV Power circuit breaker analyzer and timer.
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August 19, 2022
