Linked Questions

9
votes
5answers
2k views

Why are bulky SCR power controllers used when the same can be achieved with a relay?

This is kinda noob question. I recently got an SCR Power controller (WATLOW DIN-a-mite DB20-24CO-0000 Style B). This is the first time I actually got to test an SCR controller for myself. The input ...
5
votes
4answers
1k views

PWM 1Hz on solid state relay

I'm about to build a pid heating controller with a 1kW heater and a solid state relay. The ESP8266 can go down to 1Hz pwm frequency. So hopefully I can vary the number of active cycles per second, ...
4
votes
3answers
11k views

A question on zero crossing versus random-fire SSRs

Figure 1. I have the above mechanism, where I control a single-phase fan motor's switch. I mean instead of a mechanical switch, an AC/DC SSR is switching ON or OFF from a remote place by a constant ...
1
vote
3answers
14k views

Activating SSR for an AC motor via PWM input

I'm currently switching a single phase AC fan motor with an SSR. Here is the following SSR: http://www.crydom.com/en/products/catalog/s_1.pdf I activate this relay by applying continuous analog 10V to ...
2
votes
6answers
8k views

Confusion with TRIAC firing and zero crossing point

The reason for firing a TRIAC very close to the zero crossing point is explained as to avoid RF or EMI interference. Below is an excerpt from a book: What I'm having trouble to understand is that, if ...
2
votes
1answer
3k views

Controlling a 240V AC Universal Motor with Microcontroller, Optoisolator & TRIAC

I got an old washing machine motor(universal) laying around, that I'd like to speed control. I'm new to almost all the components mentioned above, but here is what I currently use: Microcontroller: ...
0
votes
1answer
4k views

How is the gate trigger resistor value calculated for a triac

As per the application notes of bta08-600cw, to control a three phase induction motor, for triggering the triac gate, the value of resistor is shown as 510 ohm. How is this value arrived at? What ...
0
votes
2answers
2k views

Triac drivers with or without zero-crossing detection

I've been looking at this schematic for triac control by varying the gate pulse timing. The description states that the triac switches off automatically at zero crossing and when there is no gate ...
0
votes
2answers
247 views

Light dimmer circuit, need some help with connections

So bascially, the bottom optocoupler (U5) is the zero cross detector which will send a pulse to pin 3 when a zero is detected and fire an interrupt. This interrupt will trigger a timer which will fire ...
1
vote
3answers
216 views

A question about triac output of zero crossing SSR relay

In a zero crossing SSR if the output is a triac, would the gate be fired/triggered every 180° or would the gate be applied a constant voltage all the time? I'm asking because in both cases the load ...