Most times engineers will look at the standard 30cm length of heat pipe and dismiss using it in an application because their working distance is beyond 30 cm. The same occurrence also applies to heat dissipation being over the rating of a single heat pipe.

Heat Pipe interleave in a cold plate

 Both of these issues can easily be addressed by using a properly designed heat pipe assembly. The first issue of length is easily addressed by interleaving heat pipes in a plate assembly with a nominal amount of overlap, in many cases 2 to 3 cm.

 The second issue of enhancing thermal dissipation can be addressed by using the round heat pipes in a flattened state, stacking them side by side in an assembled plate. Since the heat pipes themselves are rather inexpensive, it is good design practice to add additional pipes to improve your design margin.

 Note another inherent advantage in this concept is that this assembly now has improved built-in reliability through redundancy of heat transfer devices in the unlikely event of a single heat pipe failing.

For more questions on this article contact:

Vince Hill
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004   
Tel: +1- 847-255-4400  ext 12
Fax: +1-847-255-0192    

You may also visit: http://www.hilltech.com/

Large companies, when awarded a Federal government contract, may need to adopt a similar plan for themselves and their subcontractor, since the subcontracting plan is normally incorporated into awarded contract.

A lot of times it is difficult finding high quality reliable suppliers of transformers / inductors and still meet the flow down plans distinct goals for small, small disadvantaged, small HUBZone, WOB (women-owned small), veteran-owned small, and service-disabled veteran-owned small businesses.

We have selected unique companies that meet the high quality standards required by todays large firms for specialty transformers / inductors / CT’s (Current Transformers) / and PT’s, and also allow you to meet your flow down requirements for WOB and small business.

The flow-down process is intended to ensure that all small businesses receive “maximum practicable opportunity” to perform on Government contracts and subcontracts in accordance with public laws, regardless of the subcontracting tier.

Note:  the risk is that if a contractor fails to make a good faith effort to achieve the goals in its subcontracting plan, may be found in material breach of the contract and terminated for default.

Small business and WOB also a have advantages in terms of Subcontracting reports that are required by larger firms; Individual Subcontracting Report (ISR) and Summary Subcontracting Report (SSR).

Let us help you meet your small HUBZone, WOB (women-owned small business) flow down requirements.

For more questions on this article contact:

Alena Kamin
Customer Service Manager
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004  
Tel: +1- 847-255-4400  ext 12
Fax: +1-847-255-0192   

You may also visit: http://www.hilltech.com/

When using LED lighting in new installations LED drivers/LED power supplies with  standard universal input of 90 ~ 264VAC are not an issue since you can specify the specific voltage needed up front.

However, in many existing buildings that have dedicated electrical panels for lighting these are rated at 277VAC. In these installations LED lighting is typically not replacing all of the existing lighting. This means in these in cases in order to use these LED drivers you need a new circuit to supply 120VACVAC and a step down transformer to reduce the voltage from 277 to 120VAC.

New Class II LED Power Supplies are now coming on the market with wide ranging universal input of 90 – 277VAC which can be used on existing 277VAC lighting circuits with no voltage modification required.

Other features now standard on most LED Drivers are:

• Highly Efficient Switching-Mode Technology
• Active PFC (Power Factor Corrected)
• Built For Outdoor Wet, Damp or Indoor Dry Applications
• Silicone Encapsulated for Wet Locations (Use UL approved Water-Tight Conduit and Fittings)
• Built-in EMI Filter for Low Noise
• Rugged Rain-Proof Aluminum Extruded Case – IP65 Rated
• Over-Current and Over-Voltage Protection with Auto-Recovery
• Output Voltage Adjustable.

For adverse environments it also important to look for LED Drivers rated at 70°C at full load. Many LED Power supply de-rate to as little as 50% of rated power at 50°C.

For more questions on this article contact:

Vince Hill
LED Specialist
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004   
Tel: +1- 847-255-4400  ext 12
Fax: +1-847-255-0192    

You may also visit: http://www.hilltech.com/

Large scale solutions for energy storage present a new challenge regarding the heat produced and its effect on batteries and capacitors used for energy storage. The heat generated by the adjacent power components used in the inverter/converter often over shadows the losses created by charging and discharging batteries and capacitors.

In most cases great care is taken cool the switching devices and magnetic components however the batteries and capacitors are sometimes over looked yet they also are impacted by elevated temperatures in terms of degraded life and performance.

If liquid for cooling is available there are 8 key cold plate construction methods commonly used as a solution:

• Two Piece Gasket
• Full Buried Tube
• Sandwich Design
• Exposed Tube
• Deep Drilled
• Half Buried Tube
• Aluma Cop
• Two Piece Brazed

 Batteries and caps can be recessed into the plate to increase the conductive area and if needed additional thermal interface material is applied to increase thermal performance.

Sizes of these plates range from a few centimeters to slightly more than 2 meters.

An additional consideration is using a heat pipe assembly to remove heat from the internal structure of the capacitor or battery to the cold plate.

For more questions on this article contact:

Vince Hill
Thermal Specialist
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004   
Tel: +1- 847-255-4400  ext 12
Fax: +1-847-255-0192    

You may also visit: http://www.hilltech.com/

Large scale Lithium-ion battery technologies present a new challenge regarding enormous inrush current requirements when used in Electrical Vehicle (EV) applications. Ceramic composite resistors provide a reliable high energy resistor solution for these pre-charge events.

Modern DC converters use input capacitors as part of their power converters’ topology.  When used with a Lithium-ion battery, huge inrush currents can occur as the capacitors are charged up to the battery voltage. The inrush becomes extremely difficult to handle when using large batteries with a low source resistance, and substantial capacitance values. Combined with little and/or no charge on the capacitors, inrush currents peaking over 1000 Amperes can easily occur.

A typical solution is to use a high energy resistor in a DC pre-charge circuit, to limit inrush current without limiting the operating current. Ceramic composite resistors are made for these applications. Unlike wire wound resistors or metal film resistors where only a metal conductor is absorbing the energy, the composite resistors’ entire mass is absorbing the energy yielding incredibly high impulse energy capacity. Reliability and robustness is also greatly increased since there is no “thin wire” acting as a conducting medium.

Typically a pre-charge resistor is used between a battery and the load to:

• Prevent damaging the input capacitors.
• Protect battery cells.
• Stop the main fuse from blowing during the inrush current event.
• Prevent damaging the contactors in the circuit.

Sizes of high energy resistors range from a few kilo-joules to mega-joules.

For more questions on this article contact:

Kurt Neuswanger
High Energy Resistor Specialist
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004   
Tel: +1- 847-255-4400  ext 11
Fax: +1-847-255-0192    

You may also visit: http://www.hilltech.com/

How do you calculate input current required by the ballast?

Input current to ballast = [(NOMINAL WATTS / Power Factor) * (Power supply efficiency)] / Ballast input voltage

 Example:

 For:

NOMINAL WATTS = 10,000

Power Factor = 0.92

Power supply efficiency) = 90%

Ballast input voltage = 220VAC

 Gives:

Input current to ballast = [( 10,000 / 0.92) * ( 0.90)] / 220 = 44.47 Amps

For more questions on this article contact:

Vince Hill
UV Specialist
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004   
Tel: +1- 847-255-4400  ext 15
Fax: +1-847-255-0192    

You my also visit: http://www.hilltech.com/

Hill Technical has added new TP-S3LS ultra-low silicone gap fillers to its line of thermal interface materials. TP-S3LS pads contain less than 50 parts per million of silicone while providing 3.0 W/mK of thermal conductivity between hot components and their heat sinks. The gap filler’s minimal silicone content makes it suitable for use in silicone-sensitive applications including medical electronics, laser optics and telecommunications where silicone-based out gassing can lead to contamination and condensation issues or leave oily residues that interfere with process applications. The TP-S3 family of materials was developed by Chang Sung Corp. and is manufactured by Dongyun Electronics in South Korea.

Pads of TP-S3LS material are soft and compliant for easy compression and filling of air gaps between irregular mating surfaces. The material’s Shore 00 hardness is 55. TP-S3 pads can be used in temperatures up to 200°C, which exceeds the use range of silicone-free gap fillers. The material has a UL 94 flame class rating of V-0. Its dielectric breakdown voltage is over 5.0 kV.

New TP-S3 gap filler material is available in 210 x 297 mm (8.3 in x 11.7 in) sheets or die-cut parts. Standard sheet thicknesses range from 0.5 to 5.0 mm (0.020 in to 0.196 in).  Pricing for standard flat TP-S3LS sheets starts at $0.10 per square inch, which is below the cost of other 3.0 W/mK thermal gap fillers now available. Lower priced TP-S materials are also available with thermal conductivities of 2.0 and 1.0 W/mK.

For more information on all TP-S3LS ultra-low silicone gap filler materials, visit www.hilltech.com or contact:

Vince Hill
Thermal Account Manager
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004    
Tel: +1- 847-255-4400  ext 15
Fax: +1-847-255-0192     

You my also visit: http://www.hilltech.com/

This procedure can be seen in detail in the FAQ section of the Hill Technical Website, below are steps listed:

1. A qualified person following proper lockout procedures must perform lamp replacement.
2. Turn power off. Be sure that the irradiator and lamp have cooled before removing the lamp.
3. Disconnect all power and high voltage cable from the LIA.
4. Remove irradiator cover by removing both knobs at each end of the LIA and lifting out the assembly by its handles.
5. Place the LIA upside down on its handles
6. Remove one metal diffuser. Loosen the screws on the lamp holder to release the top bracket.
7. Disconnect the lamp leads and pull lamp out of the LIA.
8. Clean the replacement UV lamp and reflector liners with a lint free cloth and denatured isopropyl alcohol. Use latex or vinyl gloves during this step to keep the lamp free of any fingerprints.
9. Place one lamp lead and end fitting through the mounted metal air diffuser and on top of the lamp holder.   Place the loose metal air diffuser around the other lamp end and place the lamp end onto the lamp holder.

10.  Remount the metal air diffuser and place the top bracket over the lamp end and tighten the top bracket.

11.  Connect lamp leads to ceramic standoffs.

12.  Place the irradiator back in place and tighten the four knobs and reconnect the high voltage cable by matching index to index and screwing the connector cable down completely.

For more information, contact:

Vince Hill
UV Component Specialist
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004    
Tel: +1- 847-255-4400  ext 12
Fax: +1-847-255-0192    
You my also visit: http://www.hilltech.com/

These 1 watt products feature continuous output short circuit protection – a critical safety feature that protects the load circuit and the converter from dangerously high current levels in ultra miniature packages:

AM1DR-RZ (SIP7: 19.50 x 7.20 x 9.50mm) and AM1MR-Z (DIP14: 20.30 x 10.16 x 6.90mm) operate at the most commonly designed fixed inputs of 5, 12, and 24VDC (with ±10% tolerance).

 Highly regulated and protected output voltages 3.3, 5, 7.2, 9.12, 15VDC feature a tight load regulation of ±0.5% to ensure that stable voltages are delivered throughout the operating range, under all types loading conditions.

 Each of the 18 models in the AM1DR-RZ and AM1MR-Z series feature input/output isolation of 1000VDC, allowing these versatile power supplies to be configured for reverse polarity on the output or to be wired in series to create higher output voltages.

 Operating within an industrial temperature of -40°C to +85°C without derating, both the AM1DR-RZ and AM1MR-Z series are engineered to meet the IEC 60950-1 standard for use with indoor or outdoor telecommunication networks or cable distribution systems.   The components MTBF of greater than 1,500,000 hours further supports their use in applications where access for maintenance is limited or restricted. 

 RoHS compliant, all models undergo 100% production testing of their parameters to ensure the high reliability, while remaining competitively priced 

For more information, contact:

Alena Kamin
Customer Service Manager
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004    
Tel: +1- 847-255-4400  ext 13
Fax: +1-847-255-0192     

You my also visit: http://www.hilltech.com/

These blowers are designed to have a high output while running quiet with minimum energy input. The high efficiency designed motor allows only a ten degree temperature rise at its rated air output of 375 CFM at 0″ H2O. The inverter outputs a constant 230vac, three phase at 60hz thus allowing for a common input of 220vac, single phase at either 50 or 60Hz. This enables the blower to have a constant output in countries throughout the world.

An IEC 60320 shrouded male plug terminates to the blower with a 15 foot International Harmonized 3 x 1.00mm² cord set. The rotor is dynamically balanced and incorporates ball bearings providing a quiet long life. The air inlet and outlet accommodate 4″ flexible duct. Construction, materials and finishes enable us to meet MIL-SPECS and operate in harsh environments as well as in the office, lab or clean room.

See some of the custom blowers Hill Technical has created for their customers at www.hilltech.com

For more information, contact:

Alena Kamin
Customer Service Manager
Hill Technical Sales
216 West Campus Drive
Arlington Heights, IL 60004    
Tel: +1- 847-255-4400  ext 13
Fax: +1-847-255-0192     

You my also visit: http://www.hilltech.com/