A reliable repeatble AC step source for single shot AC events is the use of a large AC SSR with zero cross operation (no switch bounce or switch noise) and low voltage DC control. It can be used to test for both worse case transformer magnitzation current and capacitor inrush. Also, it can be switched remotely for safety. Your drawing has the Thermistor on the output of the bridge. But, the circuit as soldered has the Thermisor on the input, AC side of the bridge. Series/Parallel operation of NTC Thermistors is really a unique and unkown area of application for most designs. There is the condition of sharing current and also in instantaneous energy capacity. My quess for current sharing is the thermistors should be in close thermal contact in relation to thermal time constant and worse case temperature gradients. Some manufacturers are now making very large multibody in-rush limiters and treated and specified as a single device (see Ametherm MM35). What is the bridge maximum current rating? The bridge looks small for a 30 Amp repetative surge waveform. If the device was hot it might go kaboom?
@joecolchic16207 ай бұрын
great video.
@Astri.electronics
7 ай бұрын
Thank you! I'm glad you like it
@raffyturc Жыл бұрын
nice. those ntc are doing a good job at limiting inrush current. 👌
@Astri.electronics
Жыл бұрын
Yeah, although now if I would design it, I would use a capacitor instead of resistive elements. Capacitor's impedance would do the same effect while not heating up.
@ch2o2 Жыл бұрын
..why not just switching the power to your variac instead of plugging and unplugging the wires? There's this beautiful lighted switch on your power outlet that would make everything so easy. And most importantly, why not just show us all the schematic instead of just showing how you're fiddling with the wires and apologizing all the time ..you'd understand within a few seconds exactly what this is all about :) Are these 6 thermistors all connected in parallel, in series or for example 2p-2p-2p? ...no offense, you do it well and nice, just sometimes I wonder "why so awkward"?
@Palaniappan.7837 Жыл бұрын
Yo! You have instagram for your channel? I’ll follow.
@Astri.electronics
Жыл бұрын
I don't have for the channel, I only have personal where I share it all anyway @marek415
Пікірлер: 9
A reliable repeatble AC step source for single shot AC events is the use of a large AC SSR with zero cross operation (no switch bounce or switch noise) and low voltage DC control. It can be used to test for both worse case transformer magnitzation current and capacitor inrush. Also, it can be switched remotely for safety. Your drawing has the Thermistor on the output of the bridge. But, the circuit as soldered has the Thermisor on the input, AC side of the bridge. Series/Parallel operation of NTC Thermistors is really a unique and unkown area of application for most designs. There is the condition of sharing current and also in instantaneous energy capacity. My quess for current sharing is the thermistors should be in close thermal contact in relation to thermal time constant and worse case temperature gradients. Some manufacturers are now making very large multibody in-rush limiters and treated and specified as a single device (see Ametherm MM35). What is the bridge maximum current rating? The bridge looks small for a 30 Amp repetative surge waveform. If the device was hot it might go kaboom?
great video.
@Astri.electronics
7 ай бұрын
Thank you! I'm glad you like it
nice. those ntc are doing a good job at limiting inrush current. 👌
@Astri.electronics
Жыл бұрын
Yeah, although now if I would design it, I would use a capacitor instead of resistive elements. Capacitor's impedance would do the same effect while not heating up.
..why not just switching the power to your variac instead of plugging and unplugging the wires? There's this beautiful lighted switch on your power outlet that would make everything so easy. And most importantly, why not just show us all the schematic instead of just showing how you're fiddling with the wires and apologizing all the time ..you'd understand within a few seconds exactly what this is all about :) Are these 6 thermistors all connected in parallel, in series or for example 2p-2p-2p? ...no offense, you do it well and nice, just sometimes I wonder "why so awkward"?
Yo! You have instagram for your channel? I’ll follow.
@Astri.electronics
Жыл бұрын
I don't have for the channel, I only have personal where I share it all anyway @marek415