Re: [PSES] Assess risk of electric shock from charged capacitors

Just charge them up with your DC hipot tester to peak voltage when in the off state.if the circuit and your hipot tester allow. May work in some circumstances with simple front ends. Dan From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Monday, October 17, 2022 10:12 PM To:

Re: [PSES] Assess risk of electric shock from charged capacitors

I¹m curious as to the rationale behind that. It should be obvious that the power was turned off at the appropriate time. That would be demonstrated using an o¹scope, just as in the hit or miss method. What¹s different? Ken Javor Phone: (256) 650-5261 From: "doug...@gmail.com" Reply-To:

Re: [PSES] Assess risk of electric shock from charged capacitors

Ken, Yes, but I have had certification engineers hesitate or disallow using any home-brew solid state circuits to control safety testing. -Doug Douglas E Powell Laporte, Colorado USA doug...@gmail.com LinkedIn (UTC -06:00) Mountain Time

Re: [PSES] Assess risk of electric shock from charged capacitors

A simple circuit can provide disconnect at the peak of the ac waveform. Ken Javor Phone: (256) 650-5261 From: "doug...@gmail.com" Reply-To: "doug...@gmail.com" Date: Mon, 17 Oct 2022 13:08:17 -0600 To: Subject: Re: [PSES] Assess risk of electric shock from charged capacitors On the

Re: [PSES] Assess risk of electric shock from charged capacitors

On the question of probe resistance, I always recommend 100:1 probes which will have a negligible effect on overall timing. Additionally, it may be necessary to perform the test a number times to ensure the disconnect occurs at the peak of the sine wave. For me, experience has shown this may

Re: [PSES] Assess risk of electric shock from charged capacitors

Another way to go is to buy a Capacitor Discharge Tester that is made to perform the test you want. Just plug it in and press a couple buttons. There may be more on the market but the only one I know of is made by Compliance West USA, model CDT-240. We have the 15 amp version. The nice thing

Re: [PSES] Assess risk of electric shock from charged capacitors

Hi Scott: Many dual channel scopes (whether digital or analog) include an “add” function for the two channels. One channel must be inverted to measure the charged capacitance. The resistance of the two probes must be accounted for in the capacitance discharge time. (The same –

Re: [PSES] Assess risk of electric shock from charged capacitors

Scott, I very much prefer the two-channel o'scope dual-probe method using the A-B function. Alternatively a differential o'scope probe is an option, although they tend to be rather pricey. It is usually not necessary to get high speed probes as this is only line frequency. It is inadvisable to

Re: [PSES] Assess risk of electric shock from charged capacitors

In order to judge if there is no risk of electric shock from charged capacitors, it is required to measure the voltage across L and N of mains plug after the removal of power input. To avoid grounding loop between test equipment and the unit under test, an isolating transformer is strongly