Bitronics M651, Руководство пользователя, Страница: 26 / 80

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ML0039 November 14, 2013 Copyright 2013 Bitronics, LLC
3.1.1 Specifications (per section 1.3)
Power Supply Input (Auxiliary) Voltage – terminals L1(+) and L2(-)
Nominal: 48-250V dc, 69-240V ac (50/60Hz)
Operating Range:
36-300V dc, 55-275V ac (45-65Hz)
3.2 VT Inputs – VA, VB, VC, VN (See Appendix A1 and Section 1.3)
The M651 voltage (VT) signal inputs are connected to terminals 3-6 (see Appendix A1
for specific wiring configurations). Voltage signals are measured using a 12M ohm
resistor divider with a continuous voltage rating of 7kV. This ideal impedance provides
a low burden load for the VT circuits supplying the signals. Grounding of VT & CT
signals per ANSI/IEEE C57.13.3-1983 is recommended. The polarity of the applied
signals is important to the function of the instrument.
3.3 CT Inputs – IA, IB, IC (See Appendix A1 and section 1.3)
The instrument can be connected directly to a current transformer (CT). The Current
(CT) signal inputs are connected to terminals 7-12.
Several hardware options are offered for the M651 current inputs. Distinctions are
based on the current option ordered and the physical constructions.
The 1 Amp and 5 Amp current inputs, current input options 1 and 5 respectively,
feature 10-32 terminals to assure reliable connections. This results in a robust current
input (CT) connection with negligible burden to ensure that the user’s external CT
circuit can’t ever open-circuit, even under extreme fault conditions. Grounding of CT
signals per ANSI/IEEE C57.13.3-1983 is required.
Current inputs, option 1: 1 Amp input with internal current isolation transformer,
constructed with 10-32 studs as the current terminals. ( See Figure 3A for the
physical construction shown for the current terminals ). It is intended that this
meter connect to the output from the secondary of permanently installed Current
Transformers (CTs).
WARNING: DO NOT loosen existing 10-32 hardware that secures the current input
studs to the back panel. When making connections to the current input studs, use #10
ring lugs. Fasten ring lugs with the 10-32 bagged hardware (flat washer, lock washer,
and nut) provided. DO NOT OVERTORQUE. HAND Tighten with a standard nut
driver. 12 inch-pounds (1.36 N-m) is recommended, MAXIMUM torque is 15 inch-
pounds (1.69 N-m).