Update: I am pleased to report that the circuit below works perfectly. In my test it draws about 0.5 Amp on the base and 20Amp on the emitter and hardly gets warm. The real-life motor will draw double, but still miles from the limits of this transistor. (I am told this is all deducible from the spec sheet by any sophomore electrical engineer.)
So this is exactly what I wanted and solves my problem for the trivial sum of $40.
I am thoroughly astonished that the posters below could be so disparaging and foolish. It is all so unnecessary.
I would really suggest that the moderators modify the forum to allow a thread-creator to kick people off his thread. As it stands, sabotage gets a free pass.
(I have been blocked from making new posts to this thread.)
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Hello,
I have a motor running off a relay control system as shown in figure (A). I don't want to change the relay control system. It produces a 12V output and can push 18 Amps max. This all works fine.
I am changing to a new motor which can spike to 100Amps on startup, but normally draws about 40Amps. The relay cannot handle this.
I want to put NPN transistor "BUT30V" as shown in figure (B). BUT30V can handle 100 Amps.
See the specs for BUT30V of here. (I've ordered it and it's $40 shipped.)
www.st.com/content/ccc/resource/technical/document/datasheet/ae/8e/30/ce/bd/88/4a/17/CD00000772.pdf/files/CD00000772.pdf/jcr:content/translations/en.CD00000772.pdf
Will this work? I'm trying for something simple that's dead easy to wire up.
What current leakage can I expect when the relay is off?
Thanks!
So this is exactly what I wanted and solves my problem for the trivial sum of $40.
I am thoroughly astonished that the posters below could be so disparaging and foolish. It is all so unnecessary.
I would really suggest that the moderators modify the forum to allow a thread-creator to kick people off his thread. As it stands, sabotage gets a free pass.
(I have been blocked from making new posts to this thread.)
-----------
Hello,
I have a motor running off a relay control system as shown in figure (A). I don't want to change the relay control system. It produces a 12V output and can push 18 Amps max. This all works fine.
I am changing to a new motor which can spike to 100Amps on startup, but normally draws about 40Amps. The relay cannot handle this.
I want to put NPN transistor "BUT30V" as shown in figure (B). BUT30V can handle 100 Amps.
See the specs for BUT30V of here. (I've ordered it and it's $40 shipped.)
www.st.com/content/ccc/resource/technical/document/datasheet/ae/8e/30/ce/bd/88/4a/17/CD00000772.pdf/files/CD00000772.pdf/jcr:content/translations/en.CD00000772.pdf
Will this work? I'm trying for something simple that's dead easy to wire up.
What current leakage can I expect when the relay is off?
Thanks!
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