Shaft Voltage Current Monitors - Magnetic Products and Services, Inc.

Shaft Voltage - Current Monitors

VCM-E Product Line

VCM-EN in Non Explosion-Proof Enclosure

MPS’ most popular model. Applicable to Utility, Industrial, Hydro and all Rotating Machinery where monitoring of shaft current and shaft voltage on one unit is required. For the most complete protection on large, or critical machines, the VCM-E is the perfect choice. With higher shaft current measurement capacity, uninterrupted grounding, continuous monitoring via 4-20mA signals and alarms, operators are alerted to conditions such as grounding device failure or high voltage/current. VCM-E’s continuously monitor shaft voltage and/or grounding/earthing current providing three 4‑20… <br>
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VCM Rack Mount Solutions

(Presently Not Available). VCM Rack Mounts offer easy integration with other monitoring equipment. This option comes with the ability to monitor 1,2,3 or 4 separate units in one enclosure. The rack mount version with VCM-E circuitry, will fit into any standard 19″ rack. The VCM-E circuitry allows continuous monitoring of your rotating machinery(s) shaft both locally (LCD display) and remotely (4-20 mA outputs) of Peak and Average Current and Peak Voltage. With the multi-configurable options, it is like having up to 4 separate VCM-E’s in one enclosure.

VCM-EE in Explosion-Proof Enclosure

MPS’ most popular model in a protected explosion-proof enclosure. Applicable for Explosion-Proof Environments. For the most complete protection on large, or critical machines, the VCM-E is ideal due to its higher shaft current measurement capacity, uninterrupted grounding, continuous monitoring via 4-20mA signals and alarms for alerting operators to dangerous conditions such as grounding device failure or increase in shaft voltage. VCM-E’s continuously monitor shaft voltage and/or grounding/earthing current providing three 4‑20 mA output signals (per VCM-E) for remote monitoring and trending.

VCM-C Product Line
(Presently Unavailable)

VCM-CE in Explosion-Proof Enclosure

(Presently Not Available). MPS’ model for periodic “Route Type” Readings (monthly, weekly or daily) in Explosion-Proof Environments. Applicable to Petrochem, Industrial, and Hazardous Areas. Measuring shaft voltages accurately and consistently the same way every time is necessary for reliable maintenance of shaft grounding devices, and for trending of shaft voltages and currents. Readings taken with conventional meters are often misleading. These meters are intended to read alternating currents such as in electronic devices and power systems. The nature of stray currents and voltage.

VCM-CN in Non-Explosion-Proof Enclosure

(Presently Not Available). MPS’ model for periodic “Route Type” Readings (monthly, weekly or daily). Applicable to Utility, Industrial, Hydro and all Rotating Machinery where snap shots of shaft current and shaft voltage on one unit is required. Measuring shaft voltages accurately and consistently the same way every time is necessary for reliable maintenance of shaft grounding devices, and for trending of shaft voltages and currents. Readings taken with conventional meters are often misleading. These meters are intended to read alternating currents such as.

VCM-E vs VCM-C Comparison

Tracking the shaft voltage and current activity is essential on critical and/or large rotating machinery, such as utility turbine-generator units.

The Voltage-Current Monitor is available in two different models; the VCM-C and the VCM-E. Below is a comparison of the two products.

Summary of the Two Models	The VCM-E monitors continuous tracking of unit condition both locally and remote.	The VCM-C is a basic unit with push button activated local monitoring.
Feature	VCM-E	VCM-C (presently unavailable)
Local Display	Selectable for continuous display: Peak Shaft Voltage * Peak Shaft Current Average Shaft Current Power/Alarm Check (Rotary switch selectable)	Push button to display either: Peak Shaft Voltage ** Peak Shaft Current Average Shaft Current Battery Voltage (Rotary switch selectable)
Transmitter	Remote signals, 4-20 mA, proportional to: Grounding Device Current (Peak and Average) Peak Shaft Voltage	Not available
Alarms	Remote Relay contact openings and Local LED’s for: Maximum Peak Shaft voltage Maximum Shaft grounding current Minimum Shaft grounding current	Signals exceeding VCM range are indicated by the lighted overload LED, or display of 1_ _ _ when the push-to-read button is pressed.
Input Power Requirement	100-240 Vac 50/60Hz	9 Volts D.C.
Packaging Options	NEMA 4 Enclosure (Model VCM-EN) Explosion Proof (Model VCM-EE)	NEMA 4 Enclosure (Model VCM-CN) Explosion Proof (Model VCM-CE)
Number of Inputs	Two An insulated shaft grounding device for the grounding current measurement. An insulated shaft voltage sensing device for the shaft voltage measurement. (Optional)	One There is a single connection to the internal shunt from which either 1 ohm grounded current or non grounded shaft voltage readings are made through an insulated shaft grounding device.
Explosion-Proof Installation	The VCM-E is available for use in explosion proof or non-explosion proof environments. * CENELEC EExd IIB+H2 T6 Class Approved units are available.	The VCM-C is available for use in explosion proof or non-explosion proof environments. * CENELEC EExd IIB+H2 T6 Class Approved units are available.
Mounting Requirements	The current shunt should be mounted in close proximity to the grounding device. Transmitted 4-20 mA signals and alarm indications may be distributed to any location.	A separate current shunt is not required. The VCM-C is installed in series with the grounding device .
Type of Brush Required	Most types of insulated grounding device may be used.	Most types of insulated grounding device may be used.

*For dual shaft contact device usage only.
**Push Button opens grounding device cable to ground.