Still looking for the best device to run to control a 2hp 230v 15amp dust collector. Seems like everything is 110 and 10a…
Suggestions?
If you want recommendations please tell us your country.
Hello Geoffrey Mitchell Baker,
Generically, big motors need kinda special hardware. You want it to last, get a contactor or SSR that is rated properly for the load, and then you can use any smartplug type device to control that. Make sure you put a fuse/circuit breaker in the box as well.
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It is not a ESP8266, but a ESP32, but that might still be okay for you.
I would probably go for the 20A version, just to have some headspace.
NOOOOO!
The tiny relays in ESP switches are rated for resistive loads, and not for long terms. If you try to draw a 15A motor load through a 20A resistive-rated relay, you will eventually melt it down.
Follow @Sir_Goodenough 's advice.
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I am no electrical engineer, but is the dry contact design in the product not there to isolate the 20A load from the ESP switches?
High currents on relays make them weld together.
Even if they are designed to larger loads.
Contactor however have springs to force them free
I looked into the resistive relay and contactor and it looks like it is technically possible to do it with a resistive relay and up to 20A loads as long as the design make sure the transition time is low enough and the connection points are of a material that can handle the thermal load.
However, I then looked at videos of the Sonoff TH Elite and found one showing the inside where a Fanhar W15L is used as the relay and that does not look like it is designed for such situation.
I have had smart plugs rated for 10 A destroyed by a 1 A (5 v) phone charger.
Nothing unusual. 16A relay can be destroyed in a month or so with cheap 10W chinese led lamp. Some of them have enormous start current which melts contacts.
Been using both the Sonoff TH Elite POWR320D (Wifi-Tasmota)
and this breaker (TO-Q-SY2-163JZT) on Zigbee-Z2M (behind a “real” breaker)
https://www.aliexpress.com/item/1005006139125562.html
They control 240v 16.5A patio heaters, pool pump, etc.
Both were easy to integrate and no issues so far
(Sonoff requires flashing)
As recommended above, you can also use a contactor controlled by some ESP device. I use this solution for my water heater and sauna heater. Probably the safest option. I really don’t trust SSR, unless you buy the real thing (150$+, not the 10$ knockoffs from Aliexpress.)
I’m partial to functional devices. I’ve used them for years to control large motors. I like that they list all the contact ratings right on the relay.
https://www.functionaldevices.com/product/rib2401b2g/01t8X00000ML6bqQAD
Heaters are resistive loads, motor isn’t, so it’s way more delicate to control. Also heaters as resistive loads doesn’t have current spike at startup, like (some) motors, switch-mode power supplies…
Agreed. The Sonoff Elite however seems to have better components than it’s predecessor (TH16) and the Tongou breaker has a number of tresholds to prevent failure or overheating
Personally, I would test either devices and switch to a contactor on any sign of overheating.
It’s not overheating that is the issue.
It’s the contacts welding together.
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Many users understand information “20A maximum load” wrongly. “max 20A” doesn’t mean you can run, say a motor which draws 20A current when running fully loaded (possibly taken from it’s plate). It means you can run a motor which doesn’t draw more than 20A AT STARTUP. Having more that that results in contacts welding.
Note that induction motor draws appr. 2-3times nominal current at startup.
There is more going on than just the initial current pull. Motors store power in their magnetic field, when they are switched off , causes a reverse bias voltage spike. A 12v motor can release 50v. Motors also phase shift the electrical flow which increases the power factor, so they use more power than they are rated for.
The relay you use for a motor should have a motor/inductive rating. A 20 amp relay with no inductive rating is not the same as a 20 amp relay with an inductive rating.
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All good info here! Yes I don’t think I’m going to go with a smartplug device that passed the load through. But I can use a relay with feedback coupled with a current sensor to achive this end. The relays can be big and the current sensor doesn’t have to pass any voltage at all, just have the cord running through a transformer. I’m looking at this YQSIYU SSR-15DA Solid State Relay DC to AC, Input 3-32VDC to Output 24-480VAC 15A, for Industrial Automation Devices: Amazon.com: Industrial & Scientific - which can handle 15A 230v, with this: Amazon.com: JESSINIE WCS1800 Hall Current Sensor Detector 35A Current Sensor Module Board Short Circuit Overcurrent Protection Module Sensor with Overcurrent Lamp : Industrial & Scientific
as the current sensor. Do you think it would work? PS I am in Arizona, USA as the moderator asked…thanks!
What load type are fridges and freezers then?
I haven’t actually taken it apart, but based on its hard clicking sound, I think the Tongou breaker uses a contactor. So, I guess this shouldn’t be an issue? If the contacts weld together, it will either stop responding or overheat, which can be monitored. Also, I install these devices in rated metal boxes for added safety. As mentioned, if this doesn’t work, you can always use a relay and a separate contactor.