GuoLi provides relays for high voltage applications, which is notablely different from general relays by using particular impervious ceramic technology to keep
relays' contacts in sealed container that is separate from air and obtain high dielectric strength. The relays can be filled by different medium for different
application. Two kinds of medium, vacuum and high pressure gas, were normally used in GuoLi's relay.
As very few gas molecule exists in vacuum, arc hardly occurs. Ideally, it is possible to obtain dielectric strengths of 10000V per
0.1 mm in vacuum. Because there is no air in vacuum, contacts is oxidation free. Thus, vacuum relays typically have low and stable contact resistance, which is ideally
used in radio frequency (RF) condition.
Pure high pressure gas allows relays to obtain advanced dielectric strength and avoid oxidation. When relays are used
for hot switching, gas can keep contacts from high temperature burning. These relays are ideal for high in-rush capacitive make and capacitive discharge loads found in
ESD test equipment, cable test equipment and heart defibrillators. Gas-filled relays also provide low, stable leakage current in applications sensitive to current
fluctuations - especially across open contact sets over long periods of time.
Continuation for mounting and connecting.
Definition and Specifications for GuoLi's High voltage relays
Contact Arrangement -GuoLi's relays have the following contact arrangement:
- single pole single throw (SPST)
- single pole double throw (SPDT)
- double pole double throw (DPDT)
Contact Form The code name for relay model (see the figure)
- Form A: SPST-Normally Open
- Form B: SPST-Normally Closed
- Form C: SPDT
- Form 2C : DPDT
- Form P: SPST-Latching
- Form R: SPDT-Latching
Test voltage- The voltage for test relays' dielectric strength, normally showed by peak voltage ( 50 or 60 Hz), 1 minute duration.
Rated Operating Voltage - The maximum allowable AC rms voltage (50 or 60 Hz) which may be applied between open contacts or high voltage and housing
, normally showed by peak voltage ( 50 or 60 Hz), high frequency voltage is shown for RF application.
Continuous Current - The maximum current that can be carried by the closed contacts of the relay for a sustained time period.
Contact Resistance - In vacuum relays, the resistance of closed contacts is measured as voltage drop across contacts carrying 0.25 amp.
Contact Capacitance - Contact capacitance is measured either between open contacts or between contacts and ground. Measurements are made per GJB360
(similar to MIL-STD-202), Method 305, at 1 kHz.
Insulation Resistance - The minimum allowable DC resistance between two test points, such as the relay contacts and the coil, or contacts and case
at a specified voltage, usually 500 Vdc.
Coil Hi-Pot - The minimum voltage which the relay coil terminals will isolate when the relay is properly mounted.
Operate Time - The time interval between the coil energization (nominal coil voltage) and the closing of all normally open contacts. This includes
time for the coil to build up its magnetic field and transfer time of the moveable contact, and bounce time after the initial contact make.
Bounce Time - The time interval between when the contact first makes, and when the last contact make occurs.
Mechanical Life - This is the number of operations which a relay can be expected to perform while no load or voltage applied to the power contacts.
Operating Temperature Range - The ambient temperature range over which a relay is specified to operate.
Pickup Voltage - The voltage at which relays shall pickup and change its original position.
Drop-out Voltage -The voltage at which all contacts return to their "normal" positions. (Applicable only to non-latching relays.)
Coil Resistance - The DC resistance, in ohms, of the coil at 25¡ãC .
Chapter 2 Selection for High Voltage Relays Rapid selection: & GuoLi developed special relays for different applications. The chart below provides a comparison of dielectrics and contact materials
and how they perform in different applications. You can rapidly confirm the type of relays you need by the chart.
Application |
SF6 Gas |
SF6 Gas |
Vacuum |
Vacuum |
|
Tungsten/Moly |
Copper
(Special Applications) |
Tungsten/Moly |
Copper |
Carry Only
(DC) |
GOOD
But the gas increases the contact resistance resulting in less current being carried than in vacuum |
BETTER
than hard contacts but the gas increases the contact resistance resulting in less current being carried than in vacuum |
GOOD
But not as much current as copper contacts |
BEST |
Carry Only
(RF) |
N0
The gas will interfere with the RF carry capabilities |
N0
The gas will interfere with the RF carry capabilities |
GOOD
But not as much current as copper contacts |
BEST |
Make & Break
Does not apply to GuoLi reed relays |
GOOD
for make but only low currents on break |
GOOD
for make but only low currents on break |
BEST |
FAIR
Extremely low currents only |
Make
Only
Contact GuoLi for specific make and break realy ratings in your application |
BEST |
BETTER
But not as good as hard contacts |
GOOD
But not as much current as copper contacts |
FAIR
Extremely low currents only |
Long Periods of Non-Use
Or where
Low and Stable Leakage Current
Is Needed |
BEST
Only relays listed
¡°Make only¡± |
BETTER
than hard contacts but the gas increases the contact resistance resulting in less current being carried than in vacuum |
GOOD
Generally will ¡°burp¡± when HV is applied |
FAIR
Generally will ¡°burp¡± when HV is applied |
Details for selection
After confirm the approximate type of relays, the particular parameters are needed for selecting right relays. Basic principle for different applications are shown
as the following:
1. DC or low frequency non power switching application
If your application does not require power switching, the maximum voltage and current of the relays should be primarily considered, it is easy to select relays
according to High voltage relay summary . Please note that the voltage in the specification is peak voltage, DC or 50Hz (60Hz).
2. RF Application
Voltage and continuous current values are shown in High voltage relay summary for the relays that can work in RF application. From the chart, you can find
right relay rapidly. If you would like to know the relay in detail, please visit www.glvac.cn .
3. Power switching applications
Power switching applications are complicated for relays and need to analyze working conditions. The applications include make or break AC and DC power, charge or
discharge capacitor, please contact GuoLi for support.
Chapter 3 Utilizing and Mounting Relays
• Relays might be contaminated its ceramic envelope during the transfer or mount by dirty salt (such as hand sweat), which will decrease high voltage
performance and cause air discharge, surface discharge or leakage current. You had better to keep the ceramic surface clean.
• Relays should be kept from collision, which might make relays leaking, parameter changing or failing to work.
• After a period of stock, a trace of gas might release from material, which will cause one or two times current surges in vacuum relays when high
voltage is put on open contacts or contact to ground. When vacuum relays are mounted, its mounting base should be connected to ground to avoid destroying the coil power
supply circuit.
• Two mounting method, flange mounting and screw mounting, are the most common method for GuoLi's relays. When relays are mounted, please keep the
envelope and juncture of relays from transverse force.
The recommended mounting methods for relays are shown as the following drawing.
Chapter 4 Typical application for Relays:
GLVAC vacuum relays play a vital role when high power and low RF losses are required:
• Vapor Deposition For Semiconductor Wafer Processing
• Radio Antenna Tuning Matching Circuits
• T/R Switches
• Pulse Forming Networks
• Ion Implant
• TWT Power Supplies
• MRI Power Supplies
• Radar Systems
• Security Screening Systems
DC and AC Power Switching Applications
GLVAC's exclusive EPIC TM (Extended Performance Impervious Ceramic) technology contactors are the perfect solution for:
• Intrinsically Safe, Explosion Proof Applications
• Cell Site Power Systems
• Power and Battery Back-Up Systems
• Solar and Other Alternative Power Systems
• Industrial DC Power Switching
• Trucks, Boats, Mining Equipment, Light Rail, Heavy Equipment, Recreation and Emergency Vehicles
Test Equipment & Instrumentation
GLVAC gas-filled relays are great for high in-rush and stable leakage current applications, and GLVAC vacuum relays are the perfect solution for low leakage and
high carry current applications:
• ESD Pulse Forming Equipment
• Hi-pot Testing
• Cable Testing
• Motor Winding Testing
• Megohm Testing
• High Power Lasers
• Power Supply Testing
• Mass Spectrometry
• High Voltage Power Supplies
• Transformer Test Equipment
• Ballast Test Equipment
Specialized Applications
GLVAC vacuum and GLVAC gas-filled relays are excellent for:
• Airport Lighting Systems
• Geosciences Down Hole Data Acquisition
• Scientific Instrumentation
• Under-sea Power Distribution
• Sinusoidal Heart Defibrillators
Custom Solutions for Special Applications
Custom Applications
Because GLVAC Relays and Contactors are sealed to support a vacuum, they can also be filled with special gasses for custom applications. They can also be re--
packaged, tailored or tested to specific requirements:
• Super low Nano amperage leakage
• Screw terminals, long flying leads or special connectors
• Low power latching configurations
• Special packaging to replace obsolete relays
• High temperature coils for operation over 200°C
• Very low temperature applications
• High pressure oceanic applications
• Low out-gassing and ¡°Hi-Rel¡± testing with traceability and configuration controls for space and satellites