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Refer to the order guide to verify whether the meter is made with this monitoring

option. ‘V Aux’ will appear on the display as a measurement for meters equipped with

this monitoring option.

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 M650 meter 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 M650 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

Novatech Bitronics 50 Series User Manual

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