NEPSI's Medium Voltage Motor Surge Protection products protect motor insulation from power system transients.

 

  Three-Line Diagrams
  Autocad 2000 Format
  DXF Drawing Exchange Format
 

 

  
  Elevation Drawings
  Autocad 2000 Format
  DXF Drawing Exchange Format

Feel Free to Start With Above Drawing Files For Development of Specifications
  MSP, Motor Surge Protection - Standard Specification
  Microsoft Word Format
  Rich Text Format
 
If the above specifications do not meet your requirements, NEPSI will work with you to develop a specification that conforms to your specific application.


Medium Voltage Motor Surge
Protection

NEPSI's MSP (Motor Surge Protector) is designed to protect medium voltage motors from voltage surges due to lightning and switching events. The MSP accomplishes this task better than any other product in the market by decreasing the slope and crest of impending voltage surges to safe levels.
Product Scope
  • Reduced medium voltage motor failures from voltage surges due to lightning, faults, and switching events.
  • Units can be designed for direct mounting to generators, motor, and compressor housing.
  • Units can be supplied with over-current and differential protection current transformers.
  • Reduced downtime and material waste from motor failure.
  • Simple to install and requires no maintenance.
  • MSP's can be tailored or custom designed for original equipment manufacturers.

Figure 1 - Principle operation of the MSP is to decrease the crest voltage and rate of rise of the impending surge. High rates of rise damage end turns while high crest voltage damage winding to core insulation. Both of these types of damaging surges are mitigated with NEPSI's MSP.

Application

Due to the wavelength and travel time of voltage surges, the MSP is most effective when placed as close as practical to the motor terminals with the ground leads being as short as possible. This will limit the surge voltage seen by the motor to the discharge voltage of the arrester. This should be done for all critical and large medium voltage motors. Where there are many small motors or explosion proof motors in hazardous locations, a single MSP at the motor control center is recommended.

The proper choice of MSP is based on the system and/or motor voltage and the system grounding. The order guide below can be used to determine the correct MSP for your application.
Standard Features

Enclosure
11 Gauge Galvanneal Steel all welded construction. Base of unit consists of C2 steel channel for floor mounting and skidding into place. Wall mounting flanges are available for placement on suitable walls. Meets NEMA requirements for 1, 3R, 12 as standard (4X available as an option). A swing-out door with stainless steel hinges is provided for maintenance and termination..

Surge Capacitor
The MSP is equipped with hermetically sealed low-loss, low-inductance surge capacitors. Their capacitance rating is based upon the MSP voltage rating as shown in Table 1 below. The surge capacitor is equipped with discharge resistors that reduce the residual voltage on the capacitor to 50 volts in 5 minutes.

Wall mounting flanges
Allows the MSP to be mounted on a suitable wall.

Surge/Lightning Arresters
The MSP is equipped with heavy duty distribution class, silicone rubber housed MOV lightning arresters (station class are available as an option) incorporating the latest in metal oxide varistor (MOV) design techniques. The high track resistant, non-framenting silicone rubber housed arrester provides increased safety for personnel and equipment. The lightning arresters complies with the latest revision of ANSI/IEEE C62.11 "IEEE Standard for Metal Oxide Surge Arresters for AC Power Circuits.

Terminals
The MSP is provided with a Copper NEMA 2-hole pad for interconnection with customer wiring.

Operating Temperature
-40F (-40C) to +115F (+46C)

Warranty
1 year replacement on parts per NEPSI standard warranty.

Optional Features

Fuses
Provides fault protection to the capacitors and surge arresters.

Pecker-Head/Motor Terminal Mounting
The MSP can be custom designed for direct mounting to a motor or generator to act as a terminal box. The equipment can be equipped with a neutral grounding resistor, differential CTs, and ground CTs to provide all fault sensing..

 
Differential current transformers
Option shown in Figure 2 has current transformers placed inside the MSP. This option simplifies installation requiring differential protection on motors.

Figure 2 - Custom MSP Unit with Differential and Phase Overcurrent CTs
for Direct Mounting on Equipment

MSP
Ordering Guide

The MSP can be ordered by choosing the part number from the table below based on the system voltage and type of grounding. Options are ordered by adding part number suffixes.

Catalog Numbers
Motor Surge Protectors Type MSP
System Voltage Recommended Part Number
Nominal Maximum Four-Wire Wye:
Multi-grounded
Neutral 		Three-Wire Wye:
Solidly Grounded
Neutral 		Delta, Resistive
Grounded and
Ungrounded Wye
2.4 2.54 - - MSP3A0240
4.16/2.4 4.4Y/2.54 MSP3A0416 MSP6A0416 MSP6A0416
4.16 4.4 - - MSP6A0416
4.8 5.08 - - MSP6A0416
6.9 7.26 - - MSP9A0690
8.32Y/4.8 8.8Y/5.08 MSP6A1380 MSP9A1380 -
12.0Y/6.93 12.7Y/7.33 MSP9A1380 MSP12A1380 -
12.47Y/7.2 13.2Y/7.62 MSP9A1380 MSP15A1380 -
13.2Y/7.62 13.97Y8.07 MSP10A1380 MSP15A1380 -
13.8Y/7.97 14.52Y/8.38 MSP101380 MSP15A1380 -
13.8 14.52 - - MSP15A1380
20.78/12.0 22Y/12.7 MSP15A2400 MSP21A2400 -
22.86/13.2 24.2Y/13.87 MSP18A2400 MSP24A2400 -
23 24.34 - - MSP24A2400
24.94Y/14.4 26.4Y/15.24 MSP18A2400 MSP27A2400 -
For Options Add Suffixes Below

Part Number Suffixes

Station Class Lightning Arresters

S

Current Limiting Fuses

CLF
Over-Current CTs
OVCT
Pecker-Head/Motor-Generator Terminal Box Mounting
PHM
Neutral Grounding Resistor GR

Differential Current Transformers

DCT####


For differential current transformer option specify the desired primary current rating of the CT where #### appears.

For example, a MSP for a 500 HP motor that is on a 4.16kV resistive grounded system with the wall mounting brackets would have the following part number: MSP6A0416

Contact the factory or your nearest sales representative for motor housing applications and for options and voltages not shown above.

 

Figure 3 - Three-line Diagram of MSP. MSP Should Be Connected in Parallel and as Close as Possible to the Equipment Being Protected.

Notes:
1) Custom designs available on request.
2) Inside components shown as solid lines.

MSP Dimensions, Weights,
and Electrical Values
Part
Number 		H
(Inches) 		W
(Inches) 		D
(Inches) 		Capacitance Rating
of Surge Capacitor
(Micro-Farads) 		Surge Arrester
Duty Rating
(KV) 		Weight
(Pounds)
MSP3A0240 39.0 43.0 24.0 0.5 3.0 310
MSP3A0416 39.0 43.0 24.0 0.5 3.0 310
MSP6A0416 39.0 43.0 24.0 0.5 6.0 310
MSP9A0690 43.0 43.0 24.0 0.5 9.0 420
MSP6A1380 47.0 43.0 24.0 0.25 6.0 420
MSP9A1380 47.0 43.0 24.0 0.25 9.0 420
MSP10A1380 47.0 47.0 24.0 0.25 10.0 420
MSP12A1380 47.0 47.0 24.0 0.25 12.0 420
MSP15A1380 47.0 47.0 24.0 0.125 15.0 420
MSP15A2400 47.0 47.0 24.0 0.125 15.0 470
MSP21A2400 51.0 51.0 28.0 0.125 21.0 470
MSP24A2400 51.0 51.0 28.0 0.125 24.0 470
MSP27A2400 51.0 51.0 28.0 0.125 27.0 470

Figure 4 - Typical Enclosure Configuration Showing
Outside Dimensions

Note:
1) Add 8 Inches to the width dimension if the current transformer option is chosen.

Northeast Power Systems, Inc.
66 Carey Road
Queensbury, New York 12804
Phone: 518-792-4776
Fax: 518-792-5767

E-mail: sales@nepsi.com
Website: www.nepsi.com

Copyright © 1999 - 2009 Northeast Power Systems, Inc.

 

 

 

 

 

 

 

Download Medium Voltage Automatic Capacitor Bank Specification in Microsoft Word Format Download Medium Voltage Automatic Capacitor Bank Specification in Rich Text Format