Capabilities
DSI is a full service provider of high voltage insulation systems.
- Design
- Manufacture
- Testing
Customization
Although many of our products have become industry standards and are available to all, often with slight modifications to suit, they nearly all began as custom solutions. Rather than to present a catalog of our nearly 1000 designs, we have found that the best, and most efficient approach, is to deal with each requirement presented to us on an individual basis. Based on the variety of parts and building blocks available to us, we can customize a solution based often on existing, proven and available components yielding a solution more closely suited to the application.
Design Examples
It is increasingly common for rotating anode x-ray tubes to be constructed with the motor stator at high voltage so as to provide closer coupling to the rotor. Usually these three phase motors are PWM controlled using a conventional three conductor x-ray cable to bring 440 volts to the motor but floating at 75 KV or higher. Typically the cable used is a standard cathode cable and the three wires which normally carry the cathode heater current rarely see more than 25 volts between them. These cables have performed well at 440 volts until recently.
DSI research has demonstrated that an unintended consequence of replacing older SCR drive systems with those using new, faster switches with much faster pulse risetimes can transform the cable into a transmission line with the effect of doubling the 440 volts at the stator end of the cable. This tends to occur on cables over about 50 feet long. Breakdown of the insulation between the conductors can occur over an extended period of time (months) due to corona damage.
DSI has designed a cable with superior insulation integrity and higher corona inception voltage to be used in cases where the anode stator drive is at high voltage. This cable is of the same size and flexibility as a standard cathode cable. It has been in service for three years without incident.
Test Facilities
DSI maintains an extensive test facility enabling complete investigation and characterization of materials and product for both developmental and production testing. A partial listing of our testing capabilities includes:
- DC testing to 600KV
- AC testing to 100KV
- Impulse testing to 1.3MV
- AC and DC corona testing
- Insulation resistance
- Mass spec leak detection
- Environmental chamber
- Hydrostatic test vessel
- Vacuum test chambers
Materials and Environments
The wide variety of environmental requirements requires a working knowledge of materials under high voltage conditions as modified by temperature, pressure, radiation flux and a host of other factors.
Depending on the requirements, DSI may suggest an insulation system comprised of one or more of the following:
- Ethylene Propylene Rubber
- Silicone Rubber
- Polyethylene
- Polyester
- Polyimide
- Polyamide
- Polyamine
- PTFE (Teflon ™)
- Epoxy
- Urethane
- Ultem ™
- Acrylic
- PVC
- Polycarbonate
- Oil
- Gas
- Vacuum
- Alumina
- Impregnated Paper
