Medium Power

Dynapower Corporation and Rapid Power Corporation are world leaders in the design and manufacturing of medium power rectifiers serving hundreds of industrial, military, commercial, and research applications. These industrial applications require the use of direct current ranging from 1000A to 25000A for power ratings of 500kW to 2MW (crane duty rectifiers feature ratings starting 50kW). We offer both standard and highly customized designs for your rugged industrial application.

 Rectifier Cooling options for these supplies include forced-air, direct water, convection as well as a variety of closed loop systems.  Transformer options available include VPI, Epoxy Cast Coil, and Oil-Immersed construction. Our highly customizable systems also feature a variety of control and monitoring options, which include digital and analog communication for interface with an upstream PLC or computer system. 

Factory

All of our power supplies are precision engineered by our highly experienced engineering staff in our state-of-the-art 175,000 sq. ft. factory in South Burlington, Vermont  Engineering, manufacturing, and testing of the transformer and rectifier are accomplished in our factory, producing seamless subsystem integration and testing to meet or exceed the requirements set forth in ANSI 34.2.

Applications

Dynapower and Rapid Power Corporation manufacture custom designed units for applications that include:

Steel Plants - Continuous Strip - Cranes - Electromagnets - DC Shop Power Dockside Power Elevators

Electrochemical Processes - Chlorine - Hydrogen - Oxygen Electrochlorination Systems - Desalination - Hypo-chlorination

Electrowinning Processes - Copper, Cobalt, Gold, Zinc, Lithium, Silver, etc. Mining Applications - Underground Locomotive traction supplies - DC Shop Power Resistive Heating

 The basic unregulated or no control power supply contains the main transformer, power semiconductors, appropriate fusing, and power on light. On regulated units, solid state modules provide voltage regulation with current limit and are located in a sealed compartment to protect modules against adverse atmospheric conditions. Base unit protection for these supplies includes current limiting fuses are for protection of the transformer and semiconductors.

Semi-conductors

Semiconductors used for rectification are selected according to the electrical current requirement of the system and are rated to withstand normal transient voltages and surges without breakdown, offering increased reliability for all applications.

High grade, hermetically-sealed semiconductors are mounted on heat sinks and are protected with quick-acting silver sand fuses. The PRV rating of all semiconductors used is well above the ratings specified in ANSI C34.2. This increased PRV margin yields additional transient voltage protection and a higher mean time between failure (MTBF).

If semiconductors are paralleled for higher DC current requirements, provisions are made to ensure that no device will carry current in excess of the safe operating current under and steady state or normal transient condition. Semiconductors are conservatively rated to provide ample capacity for overload.

Rectifier Transformer

Our standard rectifier transformer is an isolated primary and secondary type vacuum-varnish impregnated (VPI) design. Our transformer coils are wound with continuous copper conductors (without splices or joints), vacuum-varnish impregnated, and then oven baked for protection against dust, moisture, and fumes. 

The transformer core is constructed using interleaved sheets of high-grade, grain-oriented silicon electrical steel operated a flux density designed for high efficiency. All standard ANSI configurations are available. 

Thermal-overload sensing devices are included in each leg of the transformer to detect winding over-temperature due to single phasing, overloading, or loss of cooling.    

Enclosure

Enclosures are rigid, welded, free-standing, self-supporting painted cold rolled sheet steel. The base of the rectifier assembly is a heavy duty assembly formed from structural steel members with provisions for fork lifting of the supply. 

The front and rear of the enclosure is serviceable through lockable, latch-type full length doors or panels.  Custom designs are available to the customer if access is restricted and needs to be considered in the base design. 

Enclosures are treated with two coats of a suitable primer and two coats of our standard ANSI 61 gray or a medium blue finish. Custom paint colors available upon request. 

Specifications for Power Supplies

Basic Specifications

Input Voltages:  Â	Up to 15 kV ± 5%, 3 phase
Input Frequencies:	50 or 60 Hertz, ± 2%
DC Output Voltages:	Up to 2000 VDC
DC Output Currents	Up to 25,000 Amps
DC Output Power:	Up to 2,000 kW
Note: See High Power Rectifier brochure for higher power solutions

 

Output Regulation:	≤ 6% for unregulated applications
	≤ 0.5% for regulated applications
Cooling: Â	Convection, forced air, direct water, closed loop liquid–liquid, closed loop liquid-air
Enclosures: Â	NEMA 1, 3R, 4, 4X, 12

Technical Specifications

ANSI C34.2 Industrial Service Class is the most common requirement; other classes available.

Industrial Service Rating - Standard

100% rated load current continuously at 40°C ambient temperature.

Industrial Service Rating Class (Crane Duty)

• 100% rated load current continuously at 40°C ambient temperature
• 125% for two hours following continuous operation at 100% at 40°C ambient temperature
• 200% for 10 seconds following 100% operation at 40°C ambient temperature. (Altitude 3,300 feet or lower)

Industrial Service Rating Class (Mine Duty)

• 100% rated load current continuously at 40°C ambient temperature
• 125% for two hours following continuous operation at 100% at 40°C ambient temperature
• 200% for 1 minute following 100% operation at 40°C ambient temperature. (Altitude 3.300 feet or lower)

Voltage Surge Protection

Two sets of surge suppressors are provided to protect against voltage surges from both the AC and DC sides as well as providing dv/dt protection.

Cooling

Air-cooled units are convection or forced up-draft by means of centrifugal fans/motors protected by thermal-overload relays. Low DC voltage system cooling options available are direct-water cooled, water-to-water, or water-to-air heat exchangers. 

Standard Features:

• Copper bus
• High-efficiency
• Precision shunt for control and metering*
• Copper windings with Class H insulation

Standard Protection Features:

• Semiconductor thermal sensors
• Transformer thermal sensors
• Electronic peak overload detector*
• Electronic current limit*

Optional Features:

• AC magnetic starter system
• AC circuit breaker
• AC circuit breaker with under-voltage or shunt trip
• DC circuit breaker
• Fuse monitoring system
• Fuse failure system
• Redundancy
• Individually fused semiconductors
• Regeneration (Dynamic Breaking)
• Anti-single phase protection
• Reusable filters
• Space heaters
• Analog meters
• DC switchgear
• Remote control*
• Computer interface*
• Ramp control*
• Special programming*

*Regulated units only