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desining our first DRSSCT

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LAN_403

Highschool_NHL

Mon May 22 2017, 01:54PM

Registered Member #61617 Joined: Wed May 17 2017, 12:57PM
Location:
Posts: 1

Hi everyone,

we are some students from the high School NHL from the Netherlands.
for our closing project this year we are building a DRSSTC.

we are a group of student and have found allot of information in the workings and how to build one.
with this information from different site's we were able to make a basic design and chose some components.

we have a budget to realize this project from around 500 euro and couldn't buy stuff from ebay ( it's a policy from the school)
also, it was desired not to buy from the US stock in terms of shipping time.

we have a time window of 8 weeks to realize the coil from designing, building, testing and documenting the whole process.

now haven't we build anything jet but almost design the whole thing.
so we thought let's share our designs with the real smart people here on the forum in the hope they could see some mistakes in our designs.

For the Primery
Flat coil
Coil wire diameter: 0,36 cm
Coil wire spacing: 1 cm
Center Hole Diameter 18,5 cm
Required inductance 12,7 uH

MMC

2KV 220nF (KEMET PHE448SB3220JR06)
30x parralel string of 3 in series.

total: 6KV 73,3 nF

secundary

AWG: 30
Winding height: 40 cm
coil diameter: 11 cm
45,4 uH
ratio 3,6:1
toroid major diameter: 30 cm
toroid minor diameter:10 cm
toroid cap :13,4 pf

IGBT's : HGTG30N60A4
600v
75 A constant
240 A pulsed

Fres: 141 kHz

Hv circuit:

driver circuit:

we have used tesla Map 8.0 to do our calculations.
we also have used the DRSSTC burst calculator from sigurthr

so we know our I peak is around 213 Amps.

there are also some unanswered question for us.

what is a good explanation for "derate" the translation to dutch is not very clear.
we now have chosen it in the burst calculator on 60% but don't know how u can determine it.

how do we know what our bound of the OCD is?

and how do we chose the right OCD and CS ferrite core?

can you set 2 IGBT's parallel to distribute the load? (cheap solution for buying a whole brick)

thanks in advance for any advice/feedback on our design.

]hv_cuirciut.pdf[/file]
]driver.pdf[/file]

CiscoOPA

Mon May 22 2017, 02:57PM

Registered Member #38355 Joined: Sun Oct 13 2013, 11:27PM
Location:
Posts: 4

Hi from a not-expert on all this...but figured I'd chime in with what I can answer...

derate = run at less than maximum to increase durability or for other reasons (such as high temperature, etc.)

On your HV circuit - check the gate resistors. 5.6k is not going to work correctly.

Won't dig into the driver, but if you look at the schematics for the UD2.7C it's highly refined at this point and perfect to compare to.

Blackcurrant

Mon May 22 2017, 04:49PM

Registered Member #2989 Joined: Sun Jul 11 2010, 12:01AM
Location: UK
Posts: 94

"can you set 2 IGBT's parallel to distribute the load? (cheap solution for buying a whole brick)"

have a look for an IGBT with
Positive Temperature Co-efficient for Easy Parallel Operating

1. Each IGBT device must have its own gate resistor.
2. Arrange lay-out of devices so that the current paths are symmetrical.

and instead of using copper tracks use whole areas of copper, remember a lot of current may melt your PCB

keep all high voltage parts smooth

test coil set up with a signal generator first so you get a good idea of the tuning

Gregary Boyles

Sun May 28 2017, 12:49PM

Registered Member #9039 Joined: Wed Dec 26 2012, 03:31PM
Location: Epping, Victoria, Australia
Posts: 117

DRSSTC's are rather complicated, at least with my experience thus far.
8 weeks seems a very short time frame to get one working reliably if this is your first attempt at building a Tesla coil.

You might consider a simpler SSTC, perhaps Steve Ward's mini SSTC for your first attempt.

Why won't the school let you use ebay? Ali baba instead then? Or Amazon?

There is a branch in England I believe.

You could always get your parents to purchase the bits of ebay and then put in your report that your parent sourced the parts for you.

Gregary Boyles

Sun May 28 2017, 02:35PM

Registered Member #9039 Joined: Wed Dec 26 2012, 03:31PM
Location: Epping, Victoria, Australia
Posts: 117

By the way some of the large flat screen TVs that people discard when the stop working often have big beefy FETs in them that can handle 10s of amps. So where ever dead flat screens go in Holland, go and ask them if they will let you take one apart to get the FETs (and the heatsinks they are mounted on) out of them. It is not usually those components that cause the TVs to fail. Might save yourselves some euros and contribute to re-use and recycle

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