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I'm using two AQG22205s to control my blinds. I can let the blinds go down when the up wire isn't connected and vice versa, but as soon as I connect both wires, the blinds won't move.

I have no clue as to why this is. It seems like this should work. Does anyone have an idea what could cause this behaviour? Or am I missing something? The blinds are the Ilmo 50 WT (between 0.4 and 1.1 A, depending on size of blinds, see limited datasheet). They do have intelligent obstacle detection and frozen detection. Could this be interfering, as the SSRs have an off-state leak current of 1.5 mA?

The SSRs have a max. load current of 2 A and a max. repetitive surge current of 15 A (non-repetitive: 30 A).

I coupled them with a 100 Ω, (3 W) and 0.1 μF snubber.

I've attached a simplified version of the circuit I'm using (removed xor and and logic preventing activation of up and down).

In this case, the motor only works, when the up wire, or the wire with the cross, is disconnected. I measure 230VDC (DC!) over both SSRs (1&2 and 3&4) when I'm not trying to move the blinds. When I try to move the blinds down, I measure 1 V between 3&4 (as expected) and 5 V between (1&2).

edit: Turns out, the systems works when connecting the snubbers over the motor instead of over the SSRs.

blind control

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    \$\begingroup\$ "I do measure 230Vrms over both SSRs when all wires are connected, but the SSR isn't being powered... I'm guessing this is the off-state leakage." No, that's the voltage you would get across an open switch and is correct but might not be accurate. What's the voltage across each coil when you're running in one direction with all wires connected? You might have enough leakage in the "off" coil to oppose the driven coil. \$\endgroup\$
    – Transistor
    May 3, 2021 at 12:30
  • \$\begingroup\$ The 230V is when the SSR's are off. My wording wasn't clear. I've updated the description. I've added numbers for the SSR ports, and added voltage drops. Are there any additional measurements that might be useful? \$\endgroup\$ May 3, 2021 at 14:34
  • \$\begingroup\$ I'm more interested in the voltage on the motor coils as that will determine if the "off" coil is opposing the "on" coil. So measure 2-N and 3-N where N is your neutral. \$\endgroup\$
    – Transistor
    May 3, 2021 at 14:38
  • \$\begingroup\$ When all wires are connected 2-N & 3-n read 230Vdc, when I try to move them down, they both switch to 230Vac. (but nothing happens) When I disconnect 2: 2-N reads 48V when the going down, switch is enabled (and going down) otherwise 28V (3-N reads 230Vac) \$\endgroup\$ May 3, 2021 at 15:28
  • \$\begingroup\$ Where is "230 V dc" coming from? Is that a typo? I wonder if you're getting some sort of transformer or generator action from the motor where energising one coil is generating voltage in the other. \$\endgroup\$
    – Transistor
    May 3, 2021 at 16:06

1 Answer 1

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Simple blind motors have 2 coils and a capacitor to change rotation, and should work with your configuration, as snubber impedance (100 ohm + 0.1 uF) of SSR non working is much greater compared with motor capacitor (2.5 to 7 uf). I don´t know how torque detection is working, but somehow this snubber has influence. I should remove external snubber, as the SSR have already integrated the snubber circuit, and check again. Also a resistive load (a small lamp or a resistor) in paralell with motor coils can reduce this influence. If it does not work, I can only think to replace SSR with relays. enter image description here

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  • \$\begingroup\$ It (also) didn't work without the snubber. (I'll measure voltage without them later today.) I added the snubber as I'm not sure the internal snubber would be "strong" enough when reversing the motor direction. What's the minimum resistor size you would recommend? The minimum load current for these SSRs is 20mA, should I try with 10k resistors? (That's 5W power dissipation) or can I use a larger one? \$\endgroup\$ May 5, 2021 at 7:34
  • \$\begingroup\$ I cannot say a value, I don´t know how electronics inside motor is influenced. You can check with a small lamps (like used in domestic oven or freezer). If working, increment value adding more lamps until it fails again, just to know what is needed. Other option is a 230 V relay, Connect coils to your SSR´s and contacts to motor. \$\endgroup\$
    – Bravale
    May 6, 2021 at 15:59
  • \$\begingroup\$ I tried with a 40W incandescent light bulb, it didn't work. It might be too big, I'll try and find a smaller one. In the mean time, I found this image related to the SSR I'm using. www3.panasonic.biz/ac/e/control/relay/solid-state/app_circuits/… I don't have an L or R4, maybe that's the problem? I'll try ask Panasonic how one would calculate the appropriate values for it. Or do you have an idea? \$\endgroup\$ May 7, 2021 at 8:08
  • \$\begingroup\$ Sorry, no idea about these L / R4. \$\endgroup\$
    – Bravale
    May 7, 2021 at 15:48
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    \$\begingroup\$ Turns out it works when connecting the snubbers over the motor instead of over the ssr. \$\endgroup\$ May 31, 2021 at 8:46

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