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What is ‘DBC’ substrate ? |
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| Where and why is it used in Crouzet COOLTECH ? |
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| What advantages does it offer over other materials ? |
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| What are the advantages of having an Epoxy Free Concept ? |
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| Why does the COOLTECH integrate flexible connection for power assembly ? |
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| What are the Considerations for installing multiple COOLTECH devices ? |
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| How does an overvoltage device such as a TVS (Transient Voltage Protection) transorb or MOV (Metal Oxide Varistor) react to a transient ? |
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| How does this compare to the reaction of an RC network ? |
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| Why and when would you apply each device ? |
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| What is the fundamental difference between the (TVS) transorb installed in COOLTECH and a MOV? What is the failure mode for each device ? |
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| What are the primary differences between triacs and SCRs ? |
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| When would a triac be suitable, and when would an SCR output be advisable, and why ? |
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| What is I squared t ( I ² t)? How is it calculated ? |
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| COOLTECH and the Standards ? |
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What is ‘DBC’ substrate ?
 DBC stands for Direct Bond Copper. In some cases, this material is also referred to as DCB or ‘fused copper’. DBC is a material/process that bonds copper sheeting to flat pieces of ceramic (Al2O3).. |
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Where and why is it used in Crouzet COOLTECH ?
It is used to produce electrical insulators used in high power applications requiring electrical isolation between the heat source and the metal heat conducting materials, such as the power output assemblies in SSRs |
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What advantages does it offer over other materials ?
The main attributes of DBC are that it is mechanically strong due to the copper bonding and can therefore be somewhat thinner, thus reducing thermal impedance significantly and increasing the product potential to conduct current. |
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What are the advantages of having an Epoxy Free Concept ?
Epoxy material creates two major issues if used in a Solid State Relay.
Its rigid nature creates very strong mechanical stress in the product solder joints during the heating and cooling cycling operations when the SSR is switched on an off in an application.
 That stress may lead to a rupture of the soldering areas creating a fault condition inside the relay.
Some epoxy material used inside SSRs have a high content of solids, after several cycles of normal operation, the material contained in the epoxy gets hotter and hotter and might get carbonized and eventually explode. |
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Why does the COOLTECH integrate flexible connection for power assembly ?
To avoid thermal stress resulting from the normal operation of the product
To comply with vibration and shock international standards required in some applications like HVAC for trains, Packaging Machines and any application subjected to a high vibration environment |
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What are the Considerations for installing multiple COOLTECH devices ?
The maximum current that can be carried by SSRs installed adjacent to each other may vary due to the induced heat from one product to the other, this ‘mutual heating’ relationship is true in both vertical or horizontal mounting.
The following considerations need to be taken in account with more than one product is installed on a Din Rail:
- Identify the continuous current for the application
- Identify the available space in the application
- Identifier l 'espace disponible dans l'application
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Identify in the following derating charts the required distance
between products to guarantee their proper operation
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Install the desired products
Examples of curves of downgrading |
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How does an overvoltage device such as a TVS (Transient Voltage Protection) transorb or MOV (Metal Oxide Varistor) react to a transient ?
Overvoltage devices switch on and maintain a voltage determined by the rating of the component and bypass current through them sufficient to maintain that voltage. Energy absorbed in the component is converted into heat which must be dissipated.
 Notice d'installation
Type de raccodement
- Configuration relais
- Configuration contactor
Connection |
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How does this compare to the reaction of an RC network?
RC snubber networks present a low impedance to electrical noise depending upon the value of the capacitor and bypass the entire electrical event through them. |
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Why and when would you apply each device ?
RC snubber networks present a low impedance to electrical noise depending upon the value of the capacitor and bypass the entire electrical event through them. |
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What is the fundamental difference between the (TVS) transorb installed in COOLTECH and a MOV?
What is the failure mode for each device?
A MOV is a ‘metal oxide varistor’ which is made from a metal oxide material, typically zinc oxide, and it dissipates energy through the grain structure of the device. They switch into conduction relatively slowly, but can dissipate large amounts of energy.
Transorbs are made from traditional semiconductor silicon material and are very fast to switch. They can handle large amounts of power, but only for short periods of time.
MOVs fail under shorting conditions, while transorbs typically fail open. |
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What are the primary differences between triacs and SCRs ?
An equivalently rated triac and SCR die are similar in size, but since 2 SCRs are required to carry AC current, there is twice the conduction area for SCR SSRs than for triac SSRs. Consequently, thermal performance is better for SCR relays as is di/dt, dv/dt, inrush current capability and I²t….in other words, every critical parameter is better for SCR output relays than for triac output relays. |
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When would a triac be suitable, and when would an SCR output be advisable, and why ?
TRIAC
Due to their lower cost but reduced capability, triac output SSRs should be applied in lower power and less demanding applications, in particular those with low inrush current requirements and line voltages less than 250 VAC.
SCR
SCR relays are appropriate for all applications except those with cost limitations. In general, triac output SSRs should be limited to applications with less than 25 amp loads and line voltages under 250 VAC. |
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What is I squared t ( I ² t)? How is it calculated ?
The maximum current that can be carried by SSRs installed adjacent to each other may vary due to the induced heat from one product to the other, this ‘mutual heating’ relationship is true in both vertical or horizontal mounting.
The following considerations need to be taken in account with more than one product is installed on a Din Rail:
- Identify the continuous current for the application
- Identify the available space in the application
- Identifier l 'espace disponible dans l'application
-
Identify in the following derating charts the required distance
between products to guarantee their proper operation
-
Install the desired products |
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COOLTECH and the Standards ?
International Standards :
C22.2 No. 14.95
IEC 60950 Class II certifi ed by TUV
• Degree of pollution : 2
• IEC-62314
IEC-60947-4-3 and 2 for the utilisation
categories AC-51 and AC 53a
Vibration per IEC 60068-2-6 for 35 mm
in the frequency from 10 to 55 Hz
Shock per IEC 60068-2-27 with 15 G
applied for 11 ms
RoHS Directive: 2002/95/CE
EMC Compliance :
Conducted Emission :
CISPR 11 (Class A)
Conducted Immunity :
IEC 61000-4-6 (Level 3)
Immunity to Electrical Fast transients :
IEC 61000-4-4 (Level 3)
Immunity to Lightning Surges :
IEC 61000-4-5 (Level 3)
Electro-static Discharges per :
IEC 61000-4-2 (Level 3)
Radio Frequency Immunity:
IEC 61000-4-3 (Level 3) |
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FAQ
