protecting from EMF?

So i am working on some high power geophysical transmitters which are being damaged by back emf. can anyone help me with what would be the best way to protect the instrument from this. we are mainly blowing the switching IGBT's. the transmitter is supplied DC from a 30kw powersupply, feeding a set of IGBT's which are switched at a selected frequency usually 0.5 to 2hz at 50% duty cycle into a loop of wire ranging in resistance but usually around 1 ohm. we run this at up to 150A at 150V and our loads can be very inductive, usually 300mx300m 25sqmm copper wire. im thinking diodes or caps for a bit of protection. im open to any ideas

Asked by benmerlingeo 1 year ago | last reply 1 year ago


BJT vs MOSFET? Answered

-- background: In my perpetual pursuit for designing the best, cheapest, & best performing flyback (line transformer) driver, I've decided to try out some big BJTs, which appear to have higher voltage & current ratings @ considerably lower cost. In the past, I have tried MJE3055's, which work OK, and allow the generation of thin blue arcs from a 12V supply for a few minutes until the transistor dies due to high voltage kickback or overheating. The FDP33N25 gives good results but is somewhat unreliable at 24V. So I decided to give these alluring "PHE13009" 400V 12A rated NPN BJT's a try. However driving the transistor adequately seems to be the problem. (I didn't realize these transistors would require like 5A base current w/ only HFe of 2!) It seems like almost all the "good" driver schematics utilize large $$$ FETs or even IGBTs, but almost every CRT, plasma globe, and ballast (SMPS) I took apart seem to prefer high power BJTs probably due to this exact cost difference. I was only able to get simalar performance to my 33N25 MOSFET when I stuck an additional TIP120 in as an additional darlington stage, which worked very nicely (white hot arcs) for about 1 second, then it popped! :( Since the collectors are tied together they are all exposed to >200V transients, I am sure that's what killed it. I substituted that transistor for another PHE13009 to see what would happen and with a third driving stage (2N2222) I could get somewhat acceptable results but I know I can do better. >:) - My actual questions:  * The GDP of this transistor is 40MHz, seems fast to me. (certainly faster than the 2MHz GDP of the 2N3055 which works well in my slayer exciter.) and MOSFETs have significant gate charge. ECE2630 glossed over transistors mentioning BJTs are faster, (small signal ones, anyway :P ) and some internet sources agree, but I am finding lots of sources saying the opposite! What's the deal? Which one "faster?"  * How to traditional BJTs compare to IBGTs? Which are faster/better? The datasheet for this transistor explicitly mentions its use for "high frequency ballast and switch mode applications" which implies that it is well suited for my needs. It also includes a several inductor test circuits, but other than that the datasheet is pretty bare-bones.  I'm actually a little disappointed the HFe is so low (around 2-3) @ >10A. I may require more windings on my primary and a 48v supply. (not ideal) * I know I will dissipate a little more heat due to the base current, and something I didn't consider was heat dissipated in the resistor biasing/controlling the base. (like 12V at several amps just to drive the damn thing!!) so it is worth the cost benefit of $0.5? Is there a configuration I could use that makes driving the transistor easier?

Asked by -max- 1 year ago | last reply 1 year ago


IGBT ZVS Induction Heater?

Among the many tutorials for building an induction heater out on the internet, there are two primary types. Some heaters use a ZVS circuit, and are quite simple but generally limited to a power of around 1000 watts, not enough to melt most metals. Other heaters use PLL controllers and coupling transformers to add charge the primary coil/capacitor loop, and these can be much more powerful but are significantly more complicated (and expensive) to build. It seems the limiting factor in the power of the ZVS circuits is that they can use only 2 MOSFETs, and each must conduct large amounts of current. However, if these could be replaced with IGBTs, which could conduct far more current, a much more powerful ZVS induction heater could be built. Is there any reason IGBTs couldn't be used for a ZVS heating circuit?

Posted by PleaseWork55 1 year ago


Can I replace MOSFET with IGBT in Solid State Tesla Coil?

I have a half-bridge circuit. It using IRFP460. But I want turn this driver to high power version. So I request some help! Can I use IGBT for half-bridge circuit?

Asked by james34602 5 years ago | last reply 5 years ago


What or which PNP Complementary transistor can I use with a N-Channel IGBT HGTP10N120BN 35A 1200V NPT Transistor ?

What or which PNP Complementary transistor can I use with a N-Channel IGBT HGTP10N120BN 35A 1200V NPT Transistor ? I can't find a 1200v PNP transistor. Ed.

Asked by DELETED_applegoose 6 years ago | last reply 6 years ago


Boost converter?

I am making the rwilsfor07 boost converter, I already have the timer but the mosfet isn't working; I think that didn't work but I am not sure. Should I buy another one or buy a IGBT: http://www.ebay.com/itm/IGBT-Power-transistor-FGL60N100-1000V-60A-180W-TO264-/170643487614?pt=LH_DefaultDomain_0&hash;=item27bb24fb7e#ht_2150wt_758

Asked by Kurt Gerhard 6 years ago | last reply 6 years ago


Complementary transistors

What or which PNP Complementary transistor can I use with a N-Channel  IGBT HGTP10N120BN 35A 1200V NPT   Transistor  ? I really will thank you . I'm building an H- Bridge motor drive. Ed.

Posted by DELETED_applegoose 6 years ago | last reply 6 years ago


Variable frequency drive

Hello there instructables, I have another question discussing maglev theory and i was directed that the true way to build this project was to use 3-phase power! So this question, although related, is also an entirely new project in its own right! Now to the point, i have been researching single to 3-phase conversion, and there are a few options available like rotary or static phase converters, but i have been intruiged by a device called a variable frequency drive! Okay so what i understand so far (i think) is that these convert ac to dc, run that dc through a H bridge rectifier using igbt's and then convert the 3 outputs back to ac...... okay assuming my analogy is correct so far, to my question, 1. How are the igbt's triggered in the h bridge? do they use a function generator with altering timesteps to create the seperate phases? 2. Also how are these kept in sequence with eachother? Many thanks in advance for any help you can provide!

Posted by Xmortx114145 6 years ago | last reply 6 years ago


How do I program an Arduino to be used as an interrupter in a Solid State Tesla Coil?

I want to use an Arduino as the interrupter in my Dual Resonant Solid State Tesla Coil but I do not know how to program in Arduino (or any other programming language for that matter).  The rest of my gate driver (i am using an IGBT full bridge) is a 555 timer with equal on/off time generating pulses at the resonant frequency of the coil.  The output is split into 2 parts, 1 being the direct output from the 555 and the other being the output of the 555 connected to an inverter gate.  From there both inputs are fed into MOSFETs (or some other type of transistor, I just had some switching MOSFETs laying around) that have their gates controlled by the interrupter.  I want the Arduino to take the pulse from the 555, read its frequency with pulseIn, and then read a variable resistor on the analog pins whose value will be used as the duty cycle of the pulse generated by the interrupter expressed as a percentage.  The drains of the MOSFETs will then be connected to the gates of the IGBTs that will switch 900 volts from an inverter based around a transformer from a disposible camera flash board through the primary coil.  This is the last part of my driver and then I can build the coil and post the instructable for everyone to enjoy (hopefully, i am always open to constructive criticism).

Asked by UbuntuNinja 9 years ago | last reply 7 years ago