VCM-E vs VCM-C

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 and 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
Local Display	Selectable from a rotary switch for continuous display: Peak Shaft Voltage * Peak Shaft Current Average Shaft Current Power/Alarm Check	Push button to display either: Peak Shaft Voltage **(non-grounded) Peak Shaft Current Average Shaft Current Battery Voltage (Selectable from rotary switch)
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. A shaft voltage sensing device for the shaft voltage measurement. (Optional)	One There is a single connection to the internal shunt from which either 1ohm grounded current or non grounded shaft voltage readings are made.
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	Any type of insulated grounding device may be used.	Any type of insulated grounding device may be used.

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