Image, '.ASC' and circuit description text updated 22 September 2018

Below diagrammed is the active 'inrush-limiter' for application to our unregulated linear low EMF PSU -- Inasmuch as this circuit varies from 'standard' 555 'technique' (especially as regards timing cap discharge) A cursory circuit description follows the image.

Please note that U3 and its associated circuitry provide the 'ballasting-delay' at start-up and following mains interruptions of one or more cycles' duration, whereas the circuitry of U1 detect interruptions/absence of mains power --- Both U1 and U2 are configured as monostable 'one-shots' featuring external 'rapid reset' circuitry.


To begin:

Note -- for convenience only the following discussion assumes F(mains) = 60Hz

1)
-K1 is a small mains transformer featuring a 120V primary and twin 12V, 1A secondaries. -- Note: K1 operates directly from the mains and, hence, is not controlled by the Variac.

-R2 loaded by the 'back-to-back diode action' of D1 and the b-e junction of Q1 'clip' the sinusoidal power signal (from L3) to ± V(f) of the respective semiconductors (i.e. ≈ ±0.7V).

-Owing to the highly abbreviated, 'peri-crossing' locus of the 'sample interval', acceptably abrupt slopes are achieved -- Whereas saturation and cutoff of Q1 'clean up' the crests/'zeros' for a tolerable ≈ 50% d/c mains-frequency square-wave.

-Thus (again, assuming a mains frequency of 60Hz) the waveform at the collector of Q1 is a 'train' of ≈ 50% d/c, 8.333ms 'positive' pulses...

2)
- U1 is 'programed' for an interval of slightly greater than 8.333ms (said 'overage' chosen to allow for component aging, thermal 'drift', etc).

-U1 is asynchronously 'reset' by each incoming pulse (via Q2-enforced rapid discharge of C1).

-Where input pulses (i.e. pulses apparent at the collector of Q1) occur prior to expiration of the timing interval, U1's output remains 'high'.

-Should an input pulse arrive 'late' (i.e. post time-out) U1's output will go 'low' pending arrival of subsequent input pulses.

3)
-U3 is 'programed' for an interval of ≈ 500ms --- Please note that such is non-critical and may vary dependent upon several factors (to be discussed in a subsequent post)...

-A low-level input pulse (width ≥ 25μs {typical}) apparent at Q4's base resistor (R7) will reset U3 (via Q3-enforced rapid-discharge of C2) thus initiating a 'ballasting interval'.

-D6 represents the internal 'control LED' of the opto-triac (p/n S101S05V).

-During 'ballasting', U3's output is 'high' extinguishing D6 (via the circuit including Q5 and Q6) thus 'gating' the triac (not shown) off and opening the mechanical contactor (also not shown).

-The ballast resistor (not shown) no longer bypassed by the contactor is, hence, 'in series with' (i.e. 'ballasting') the main PSU.

4)
-Following time-out of the ballast interval U3's output returns to 'low'

-The triac section being 'gated on' upon illumination of the internal LED (via the circuit including Q5 and Q6) closes the mechanical contactor via completion of electrical connection of its (120V, 100mA ) actuator-coil to the mains.

-Closure of the mechanical contactor bypasses the ballast resistor thus connecting the main PSU directly to the mains.

-Notice: To prevent false switching of the opto-triac, the mechanical contactor's coil must be bypassed by a snubber network! -- A discussion of this issue will be offered for interested readers in a later post....

Please note that I have attached both the schematic file and my model for the LM7809 to this post --- Should you be unable or unwilling to 'eff around' with adding the model to your Spice installation, you may, of course, replace the subcircuit-PSU with a 9V DC 'voltage source' that said, power-fail analysis requires retention of C5...

Please know that I intend to post several simulation 'screenshots' of various points/conditions as soon as time permits (sometime this week)...

And - Because many refuse to open 'attachments' -- Below is the 'copy and paste-able' text of the LM7809 model (Aluminium hats available upon request):

////// Begin LM7809 Netlist//////

.SUBCKT LM7809 Input Output Ground

*
*(Note by 'Hypatia's Protege') -- This is my 'quick and dirty' dedicated LM7809 adapted from a generalized LM78XX model exhibited/authored? by Yuri Belenky...
*
*
*Note that the following are 'hard wired' (i.e. coded as 'immediates') consistent with a fixed Vout ~ 9V.
*
*Gain*Feedback product ('AV_Gain') := 924.15.
*Quiescent current adjustment resistance ('R1') := 1836 Ohms.


* Note: This model will allow some current flow to 'Node 0' - such
* is not part of the actual EMF regulator circuit.
*
* Band-gap EMF source:
*
* The source is off when Vin<3V and fully on when Vin>3.7V.
* Line regulation and ripple rejection) are set with
* Rreg= 0.5 * dVin/dVbg. The temperature dependence of this
* circuit is a quadratic fit to the following points:
*
* T Vbg(T)/Vbg(nom)
* --- ---------------
* 0 .999
* 37.5 1
* 125 .990
*
* The temperature coefficient of Rbg is set to 2 * the band gap
* temperature coefficient. Tnom is assumed to be 27 deg. C and
* Vnom is 3.7V
*
Vbg 100 0 DC 7.4V
Sbg (100,101),(Input,Ground) Sbg1
Rbg 101 0 1 TC=1.612E-5,-2.255E-6
Ebg (102,0),(Input,Ground) 1
Rreg 102 101 7k
..MODEL Sbg1 VSWITCH (Ron=1 Roff=1MEG Von=3.7 Voff=3)
*
* Feedback stage
*
* Diodes D1,D2 limit the excursion of the amplifier
* outputs to being near the rails. Rfb, Cfb Set the
* corner frequency for roll-off of ripple rejection.

*
* The opamp gain is given by: Av = (Fores/Freg) * (Vout/Vbg)
* where Fores = output impedance corner frequency
* with Cl=0 (typical value about 1MHz)
* Freg = corner frequency in ripple rejection
* (typical value about 600 Hz)
* Vout = regulator output EMF
* Vbg = bandgap EMF (3.7V)
*
* Note: Av is constant for all output EMFs, but the
* feedback factor changes (hence the AV_Feedback product's role in determination of Vout).
*
Rfb 9 8 1MEG
Cfb 8 Ground 265PF
Eopamp 105 0 VALUE={2250*v(101,0)+924.15*v(Ground,8)}
Vgainf 200 0 {924.15}
Rgainf 200 0 1
*Eopamp 105 0 POLY(3),(101,0),(Ground,8),(200,0) 0 2250 0 0 0 0 0 0 1
Ro 105 106 1k
D1 106 108 Dlim
D2 107 106 Dlim
..MODEL Dlim D (Vj=0.7)
Vl1 102 108 DC 1
Vl2 107 0 DC 1
*
* Quiescent current modelling
*
* Quiescent current is set by Gq, which draws a current
* proportional to the EMF drop across the regulator and
* R1 (temperature coefficient .1%/deg C). R1 must change
* with output EMF as follows: R1 = R1(5v) * Vout/5v.
*
Gq (Input,Ground),(Input,9) 2.0E-5
R1 9 Ground {1836} TC=0.001
*
* Output Stage
*
* Rout is used to set both the low frequency output impedence
* and the load regulation.
*
Q1 Input 5 6 Npn1
Q2 Input 6 7 Npn1 10
..MODEL Npn1 NPN (Bf=50 Is=1E-14)
* Efb Input 4 VALUE={v(Input,Ground)+v(0,106)}
Efb Input 4 POLY(2),(Input,Ground),(0,106) 0 1 1
Rb 4 5 1k TC=0.003
Re 6 7 2k
Rsc 7 9 0.275 TC=1.136E-3,-7.806E-6
Rout 9 Output 0.008
*
* Current Limit
*
Rbcl 7 55 290
Qcl 5 55 9 Npn1
Rcldz 56 55 10k
Dz1 56 Input Dz
..MODEL Dz D (Is=0.05p Rs=3 Bv=7.11 Ibv=0.05u)
..ENDS
*$
////// End Netlist //////


Very best regards
HP

 

Yer so purty......oh, scuze me...what were we talking about?

KL7AJ tnx for compliment! So anyhow all I'm saying is LtSpice doesn't make sharing simulations that have 3'rd party models vry easy! So if you know better way plz let us know!

...was there a method of automatically importing 3'rd party component models when loading schematic files containing references thereto

HP I say it's totally crazy of them making ppl jump through all those hoops just to share schematics with user modeled parts! Cuz after all internet is totally interactive environment and usually wants ppl 2 share way too much! So now Linear Tech is making it hard 2 share something that's actually worth sharing? So there's probably easier way but I can't find it!

'll post a capture of the 'SoftStart' schematic (accompanied by a cursory circuit description), the associated Ltspice schematic file (i.e. '.asc') and the LM7809's model/'netlist' in textual format (as well as a link to the 'subckt' file residing in my blog) to this thread. -- Thence an inquiry to the 'General Electronics Chat' forum Re: possible 'portability' of third-party component models (as per your concerns expressed in post #1588)

HP I see you did all that EXCEPT inquiry so where is it?

 

HP sry but I say it's HUGE mistake omitting series fixed resistors from R1 and R4 cuz you have 2 know some idgit will definitely adjust them too low and toast Q2/Q3 (plus prolly trimmer{s} too) and put blame on your circuit instead of their carelessness! Just sayin'

So I totally like how circuit gets around iffy _level-sensitive trigger_ using external discharge BJTs! But based on real world experiments I say saturation impedance of internal discharge transistor is totally too high anyhow! So I say circuit is 2X improvement!

HP OBTW u were 100% correct abt ppl wanting to just use 556 (which for ppl who don't know is just two 555s in 14 pin package) cuz I have 3 emails already asking that! So since it's YOU who has like a _hate_ on for 556 I just referred them 2 you!

So anyhow I have more (mostly good) things 2 say abt circuit but no time until later on!

 

So since it's YOU who has like a _hate_ on for 556 I just referred them 2 you!

... what's so bad about using a 556? I find those chips rather convenient.

 

... what's so bad about using a 556? I find those chips rather convenient.

Cmartinez you'll totally have to ask @Hypatia's Protege abt that cuz I'm not 100% sure either? FWIW I think her problem with 556 has 2 do with pinout making pcb layout harder or something like that, cuz they're electronically exactly the same!

So talking abt multiple 555 packages, I say 558 had nice improvement of edge-triggering but it basically bombed cuz 4 timers in 16 pin package meant some really bad compromises (like for example common CV and Reset lines) and also it had just OC outputs instead of way more convenient _totem pole_ stage (maybe cuz of die temp issues?)

So anyhow abt 556, I don't see ELECTRONIC problem with that at all for HP's circuit! But that's just my opinion so @Hypatia's Protege I'm asking what's the deal?

 

HP I see you did all that EXCEPT inquiry so where is it?

No time at the moment -- IMNSHO basal courtesy dictates that one makes time for response to answers prior to making inquiries!

HP sry but I say it's HUGE mistake omitting series fixed resistors from R1 and R4 cuz you have 2 know some idgit will definitely adjust them too low and toast Q2/Q3 (plus prolly trimmer{s} too)

Point taken -
-R1 will be replaced with a 10kΩ multi-turn trimmer in series with a 4.7kΩ, 0.125W 'fixed value' resistor.
-R4 will remain a 1MΩ multi-turn trimmer but in series with a 4.7kΩ, 0.125W 'fixed value' resistor.

Said changes to be reflected on all representations of the circuit (i.e. images and schematic files) here and elsewhere following the next 'update' on or prior to Sep 23.

As an aside:

cuz you have 2 know some idgit will definitely adjust them too low

---Emphasis Added---

Must we be at war with our readers? -- Such misadjustment is all too easy --doubly so with multi-turn trimmers offering no outward indication of position! -- Ya know? Having verily 'chased' Theo away based upon 'attitude', perhaps some introspection is in order?

So since it's YOU who has like a _hate_ on for 556 I just referred them 2 you!

... what's so bad about using a 556? I find those chips rather convenient.

@Aleph(0) --- I'd hardly say I had a 'hate on' for the LM556

But to continue - It has long been my experience that 'creative layout' of analog/mixed signal systems is augmented via implementation by up to a few small units as opposed to a monolithic block (bloc?) of identical units featuring no useful interconnections -- That said - the LM556 will be fine for anyone wishing to employ said device! -- Stay away from the LM558 though!

Very best regards
HP

 

While browsing for some other stuff, I stumbled upon this cheap-o brand inductance meter.

https://m.banggood.com/LC200A-Digital-LC-Handheld-Inductance-Capacitance-Multimeter-p-946910.html

It doesn't look as sophisticated as the one I previously recommended, but it's so cheap that it might be worth considering as a poor-man's alternative.

 

While browsing for some other stuff, I stumbled upon this cheap-o brand inductance meter.

https://m.banggood.com/LC200A-Digital-LC-Handheld-Inductance-Capacitance-Multimeter-p-946910.html

It doesn't look as sophisticated as the one I previously recommended, but it's so cheap that it might be worth considering as a poor-man's alternative.

Thanks for that! While, as previously discussed, the Peak (Atlas) is ideal, the availability of an acceptable low cost 'fallback' is quite in keeping with our sincerely declared 'mission' Re: maintenance of accessibility to all interested parties without regard to financial means!

@cmartinez , @shortbus, @The Electrician, @#12 and all others offering product/alternate approach suggestions -- please be advised that it is our plan to 'gather' your contributions (past, present and future) to a blog entry (via the fora 'quote' feature such that your advice will remain verbatim and with full attribution) for linked reference under 'suggested alternatives' in appropriate tutorial passages -Subject to your item-by-item permission, of course!

Very best regards
HP

 

--Image and .ASC amended 22 Sep 2018


Kind friends

Re U1 only! -- While a fully discharged timing cap (C1) at startup or upon recovery from brief power interruptions, 'bounce', etc is not essential to operation of the circuit under 'normal' conditions - It occurs to me that a full initial 'pulse detection' interval may be desirable under certain 'exotic' conditions possible when operating from 'frequency labile' mains/generating equipment -- Hence my connection of the internal discharge BJT's collector (i.e. pin 7) to the positive terminal of the timing capacitor (please see below).

Note that while I generally dislike and avoid use of the internal discharge BJT, The described function is non time (i.e. speed) critical...
//////////////

Additionally, as per @Aleph(0)'s suggestion, I've placed 'limit resistors' in series with R1 and R4.

Best regards
HP

 

-Subject to your item-by-item permission, of course!

About our earlier arguments and disagreements and my childish refusal of permission to use my drawings or any other thing I added to the thread, I here by reverse my refusal. While I can't get back any of my text that I deleted, I still have most of the drawings/sketches if you need them.

 

I tell you that in the same way there will be more rejoicing in heaven over one sinner who repents than over ninety-nine righteous persons who do not need to repent. .... Luke 15-7

 

I tell you that in the same way there will be more rejoicing in heaven over one sinner who repents than over ninety-nine righteous persons who do not need to repent. .... Luke 15-7

There were things happening behind the scenes at the time, that are no longer in play.

 

About our earlier arguments and disagreements and my childish refusal of permission to use my drawings or any other thing I added to the thread,

Hey, @shortbus -- No need for self-recrimination! - Emotions were running over-high all around!

I here by reverse my refusal. While I can't get back any of my text that I deleted, I still have most of the drawings/sketches if you need them.

Many genuine heartfelt thanks!

Hey @shortbus - please know that it was neither our intent nor desire that all your content was 'scrubbed' from this thread (@Aleph(0) and I have discussed this on several occasions and are in full agreement on this point) -- FWIW I can but guess said action owed to a misunderstanding between Aleph(0) and the moderator -OR- perhaps the moderator assumed your revocation of 'publication rights' to your recent suggestions (e.g. annotated drawings, etc...) extended to all of your contributions to this thread? -- In point of fact we found the vast majority of your posts (i.e. all but the bickering at the last) to be civil, pleasant and very often edifying...

So - the (potential) good news -- My experience with administration of 'chat fora' leads me to believe that your content may be restored via this thread's 'edit history'/'moderation cache' (or Xenforo's equivalent thereto) -- hence my proposal that @Aleph(0) (being, as she is, this thread's 'TS') open a 'PM' with the moderator in question, you and I that we might request/discuss restoration of your content --- A scant fortnight's bickering should not negate over two years' civil, constructive participation

I expect @Aleph(0) to login this Saturday at the latest - additionally I've emailed her on this subject --- Please watch your PM inbox

OBTW -- In case you're wondering why our offer of requesting restoration of your content waited until now? -- It is merely that, prior to viewing your last posts (i.e. #1607 and #1609), I was uncertain you would welcome said intervention...

With utmost sincerity
HP

PS -- And yes!-- I'm ashamed to confess that 'behind the scenes influences' had me seeing 'trolls under the beds' as well

 

HP just to let u know we've totally been getting lots of requests 4u2 post diagram of WHOLE circuit including complete opto-isolating triac, EM contactor and ballast resistor! So anyhow I sent _broadcast_ saying that u aren't abt to model any more 3'rd party components (cuz of problem getting them imported to other ppl's installations) but consensus is that they just want to see whole picture for context (so they aren't asking for .asc of that, just schematic image)!

 

Hey, @shortbus -- No need for self-recrimination! - Emotions were running over-high all around!


Many genuine heartfelt thanks!

Hey @shortbus - please know that it was neither our intent nor desire that all your content was 'scrubbed' from this thread (@Aleph(0) and I have discussed this on several occasions and are in full agreement on this point) -- FWIW I can but guess said action owed to a misunderstanding between Aleph(0) and the moderator -OR- perhaps the moderator assumed your revocation of 'publication rights' to your recent suggestions (e.g. annotated drawings, etc...) extended to all of your contributions to this thread? -- In point of fact we found the vast majority of your posts (i.e. all but the bickering at the last) to be civil, pleasant and very often edifying...

So - the (potential) good news -- My experience with administration of 'chat fora' leads me to believe that your content may be restored via this thread's 'edit history'/'moderation cache' (or Xenforo's equivalent thereto) -- hence my proposal that @Aleph(0) (being, as she is, this thread's 'TS') open a 'PM' with the moderator in question, you and I that we might request/discuss restoration of your content --- A scant fortnight's bickering should not negate over two years' civil, constructive participation

I expect @Aleph(0) to login this Saturday at the latest - additionally I've emailed her on this subject --- Please watch your PM inbox

OBTW -- In case you're wondering why our offer of requesting restoration of your content waited until now? -- It is merely that, prior to viewing your last post (#1609), I was uncertain you would welcome said intervention...

With utmost sincerity
HP

PS -- And yes!-- I'm ashamed to confess that 'behind the scenes influences' had me seeing 'trolls under the beds' as well

@shortbus I totally agree with HP! All of your posts (except last few where we were ALL getting out of line) were definite asset to thread! So I'm saying even if you deleted them yourself it should be possible to restore them with help of mod! So If you'd like that just let me know and I'll start PM with mod and the three of us (HP, you and me) 2 see what can be done!

PS -- And yes!-- I'm ashamed to confess that 'behind the scenes influences' had me seeing 'trolls under the beds' as well

HP me too! So I don't consider myself 2b easily manipulable but I totally underestimated power of subtle political innuendo and _us vs them_ rhetoric! So that's not excuse just embarrassing truth

 

including complete opto-isolating triac, EM contactor and ballast resistor!

Let us not forget the snubber!

I'll get to it ASAP -- Be advised that it mightn't be prior to the weekend, however...

Best regards
HP

 

So I'm saying even if you deleted them yourself it should be possible to restore them with help of mod!

Yes, I spent a lot of time going through and deleting my content. And it seems like you and HP know who the behind the scenes influence was. On both sides there were interactions and attempts of interaction. He has since gone on to be banned from 2 other sites that I'm aware of since the ban here. Makes it like 18 or 19 sites and counting now that he is persona non grata.

 

And it seems like you and HP know who the behind the scenes influence was.

Indeed! If ever a man was 'poisoned' by his own political ardor... -- Perhaps he'll return to his better nature following 2020 - One can but hope...

Very best regards
HP

 

Attention: Readers reporting overheating/burnout of R10:

Please be advised that my selection of R10 represents the nearest standard fixed resistor value consistent with I(D6_target) ≈ 30MA -- Hence:
R10(ideal) = [VCC-VF{D6}]/I{D6} = (9V-1.2V)/30mA = 260Ω ≈ 270Ω -- for an I(D6_actual) ≈ 28.89mA (of course I{R10} = I{D6})

Hence - PD(D6) = [VCC-VF{D6}]^2/R{R10)} = [9V-1.2V]^2/270Ω≈223.3mW (i.e. just 'shy' of 1/4 Watt) -- Be advised, however, that good practice will employ a 1/2 watt resistor...

All of which is to say: Sincere apologies for my failure to properly annotate R10 on the image and in the '.ASC' -- leaving, as I did, the impression an 1/8'th Watt resistor was 'up to the job'! -- Please see the corrected schematic (below)...
//////////

As per your requests -- Following are the adjustment instructions:

Having constructed the circuit as shown and assuming 10-turn linear trimmers:

U1
1) 'Ballpark' R1 via adjusting same for an interval slightly greater than the calculated line-derived pulsewidth (i.e. R1 > [5/{11*C1*F_Line] - 4.7kΩ).
i.e. ≈ 3kΩ or ≈4.5kΩ for line frequencies of 60Hz or 50Hz respectively.

2) With power applied to the circuit, observe U1-pin 3 with a TDO or (≥ 10MHz/≤100ns) 'logic probe'.

3a) If pulsation is indicated, increase R1 just enough to achieve a stable 'high state'.
3b) In the absence of pulsation, decrease R1 until pulsation in noted, then increase R1 just enough to achieve a stable 'high state'.

4) Further increase R1 to protract the timing interval an additional ≈ 1ms (i.e. an additional ≈ 1kΩ resistance ≈ one additional turn of the suggested trimmer).

U3
1) Adjust R4 for an interval ≥ 500ms (i.e. ≈ 450kΩ ≈ 4.5 turns of the suggested trimmer).
2) Operationally verify that the timing interval is indeed ≥ 500ms prior to connection of a reactive load!
3-note) The above will provide a 'safe starting point' -- final adjustment of R4 will be discussed in a later post.

HP just to let u know we've totally been getting lots of requests 4u2 post diagram of WHOLE circuit including complete opto-isolating triac, EM contactor and ballast resistor! So anyhow I sent _broadcast_ saying that u aren't abt to model any more 3'rd party components (cuz of problem getting them imported to other ppl's installations) but consensus is that they just want to see whole picture for context (so they aren't asking for .asc of that, just schematic image)!

Inasmuch as I'm right out of time - Such must await @Aleph(0) 's return to the fora (Tuesday) -- Note - those unfamiliar with thyristor switching characteristics and/or snubber design are strongly advised to await publication of the diagram/discussion referenced in Aleph's post (quoted above) prior to connection of the contactor (or other reactive load) -- In the meantime you may 'safely' test the circuit via a principally resistive load (e.g. a 100W line 'voltage' incandescent lamp).

Note: mitigation of electric shock hazard/preclusion of possible test equipment damage requires use of an isolated (i.e. Non ground-referenced) 'mains voltage' source when testing the triac load circuit!

Very best regards
HP

 

Attention: Readers reporting overheating/burnout of R10:

Please be advised that my selection of R10 represents the nearest standard fixed resistor value consistent with I(D6_target) ≈ 30MA -- Hence:
R10(ideal) = [VCC-VF{D6}]/I{D6} = (9V-1.2V)/30mA = 260Ω ≈ 270Ω -- for an I(D6_actual) ≈ 28.89mA (of course I{R10} = I{D6})

Hence - PD(D6) = [VCC-VF{D6}]^2/R{R10)} = [9V-1.2V]^2/270Ω≈223.3mW (i.e. just 'shy' of 1/4 Watt) -- Be advised, however, that good practice will employ a 1/2 watt resistor...

All of which is to say: Sincere apologies for my failure to properly annotate R10 on the image and in the '.ASC' -- leaving, as I did, the impression an 1/8'th Watt resistor was 'up to the job'! -- Please see the corrected schematic (below)...
//////////

As per your requests -- Following are the adjustment instructions:

Having constructed the circuit as shown and assuming 10-turn linear trimmers:

U1
1) 'Ballpark' R1 via adjusting same for an interval slightly greater than the calculated line-derived pulsewidth (i.e. R1 > [5/{11*C1*F_Line] - 4.7kΩ).
i.e. ≈ 3kΩ or ≈4.5kΩ for line frequencies of 60Hz or 50Hz respectively.

2) With power applied to the circuit, observe U1-pin 3 with a TDO or (≥ 10MHz/≤100ns) 'logic probe'.

3a) If pulsation is indicated, increase R1 just enough to achieve a stable 'high state'.
3b) In the absence of pulsation, decrease R1 until pulsation in noted, then increase R1 just enough to achieve a stable 'high state'.

4) Further increase R1 to protract the timing interval an additional ≈ 1ms (i.e. an additional ≈ 1kΩ resistance ≈ one additional turn of the suggested trimmer).

U2
1) Adjust R4 for an interval ≥ 500ms (i.e. ≈ 450kΩ ≈ 4.5 turns of the suggested trimmer).
2) Operationally verify that the timing interval is indeed ≥ 500ms prior to connection of a reactive load!
3-note) The above will provide a 'safe starting point' -- final adjustment of R4 will be discussed in a later post.



Inasmuch as I'm right out of time - Such must await @Aleph(0) 's return to the fora (Tuesday) -- Note - those unfamiliar with thyristor switching characteristics and/or snubber design are strongly advised to await publication of the diagram/discussion referenced in Aleph's post (quoted above) prior to connection of the contactor (or other reactive load) -- In the meantime you may 'safely' test the circuit via a principally resistive load (e.g. a 100W line 'voltage' incandescent lamp).

Note: mitigation of electric shock hazard/preclusion of possible test equipment damage requires use of an isolated (i.e. Non ground-referenced) 'mains voltage' source when testing the triac load circuit!

Very best regards
HP

HP tnx SO much for that cuz it already made my gmail inbox a way calmer place! But I also say you're definitely being too gracious taking all the blame! Cuz I say ppl should know that 0.125W resistor is too low power for ballasting optoisolator's LED! Cuz after all we're not here 2 teach Ohm's law!

HP also HUGE thanks for posting timer adjustment instructions cuz some ppl just can't understand how U1 works 2 detect power interruption so they don't know how to set it up at all. So I say when u post output circuit (by which I mean triac, EM contactor, snubber and startup ballast resistor) maybe u should include block diagram of entire softstart circuit to help comprehension?

inasmuch as I'm right out of time - Such must await @Aleph(0) 's return to the fora (Tuesday)

So just being clear, HP plans 2 draft and post diagram so she's waiting until I can be here to answer questions cuz she's vry busy as usual So I know she said Tuesday but Wednesday definitely wks better for me so u can definitely plan on me being available to help out with questions starting then.

Now abt email questions, comments and all feedback! Just so you know they will not be answered personally to your E! We only answer them here on this thread and sometimes HP's Provo fora! That's it! So we totally promise NOT to publish your names, addys or like that but just so u know substance of email questions is NOT private!

So to ppl insisting to ask questions by e instead of on thread (which I know as fact that some of you are AAC members) I could be all thin skinned and ragey thinking u don't want 2b associated with us! So instead, (for sake of my BP) I think mostly it's ur embarrassed publicly asking questions u think on as too _basic_? So if that's it plz don't be silly! Nobody's an expert at everything (least of all us)! Nobody's judging you! So when we sometimes _scold_ ppl for not thinking it's always general! Never personal! Unless it's someone we know will take it in friendly spirit intended.

So like _putting my pride where my mouth is_ for perfect example of me asking basic question abt totally fundamental concept plz just look HERE! So anyhow I totally agree with adage saying _there's no such thing as a stupid question_ as long as it's genuine!



ETA @shortbus if it's ok with you, sometime Wednesday I plan to start PM (with Mod, you and HP) abt restoring your content! So just speculating (cuz I'm not _Xenforo savvy_) there's prolly two possibilities:

◊It might be possible to just restore all your past content en masse to thread (then if u wanted, u could just 'weed out' anything u didn't like but we wouldn't insist on that at all!)

◊It's also possible posts would have 2b restored one by one which would be a lot of work for Mod. So if that's case maybe best way is to just restore what you consider highest-value posts?

@Shorbus so anyhow, how and what's done is totally your and Mod's call! All I'm saying is that as TS I'm ok with whatever works!

Here's vry important note to Mod: I hope u don't think I'm like _objectifying_ you by not referring 2 u by your UN! It's just that I don't know if ur ok with that in public discussion of Mod action!