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Author Topic: Solarimmersion died what should I replace it with  (Read 1555 times)
Tinbum
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« Reply #15 on: April 03, 2020, 04:22:33 PM »

You can't switch an inductive load on and off many times a second. You will blow it or something else in the circuit up.

Have a read of the instructions for an SSR.
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85no 58mm solar thermal tubes, 28.5Kw PV, 3 x Sunny Backup 5048, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, Atmos wood gasification boiler, Brosley wood burner, 2000lt buffer tank and 250lt DHW
pj
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« Reply #16 on: April 03, 2020, 05:14:44 PM »

You can't switch an inductive load on and off many times a second. You will blow it or something else in the circuit up.

Have a read of the instructions for an SSR.

From the Fotek SSR25DA spec sheet:-
"specially suited to control resistive, capacitive and non-saturated inductive loads"

From a Crydom Whitepaper:-
"Solid State Relays (SSRs) and Solid State Contactors (SSCs) are ideally suited for
controlling dynamic loads such as motors"
http://www.crydom.com/en/tech/white-papers/ac_mc_whitepaper.pdf

I have a Resol Controller for my Solar Thermal, and it can vary the speed of the pump - I can set it in 10% increments from 30% to 100%. It uses a Solid State output, not a mechanical relay. Can you advise how this is achieved?
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pj
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« Reply #17 on: April 04, 2020, 12:46:36 PM »

You're right Tinbum, high speed PWM on certain classes of electric motor will cause smoke etc. Based on what I have read, it depends on the type of motor, and power rating etc.
Seems that these motors are ok when running, and ok when stopped (duh), but inbetween can be quite lossy. PWM can keep them in this inbetween state, and the losses can lead to overheating and failure.
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North Hampshire
Gareth J
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« Reply #18 on: April 09, 2020, 09:50:47 AM »

Because your panel setup is only 2kw, you will never out generate the capacity of whatever solar diverter you use (they're all 3kw+ as far as I'm aware)

With this in mind, you can simply add more resistive loads to the circuit. Nothing will go bang, the diverter doesn't care if it's heating a 3kw immersion coil or a 10kw load. Bad things only start to happen if you potentially overload the diverter and that'll only happen if you exceed 3kW diverted power.

You can then switch in/out additional loads either manually, with relays, or smartly.

Have been running a solic200 feeding an old storage heater circuit with 3heaters on it. It can never divert more than 2.5kw (due to generation limit) so I switch them on/off manually or just leave them all on sometimes.

Note; an overnight boost timer will need to be separate and pick only the one load.
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Tinbum
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« Reply #19 on: April 09, 2020, 10:42:08 AM »

You can't switch an inductive load on and off many times a second. You will blow it or something else in the circuit up.

Have a read of the instructions for an SSR.

From the Fotek SSR25DA spec sheet:-
"specially suited to control resistive, capacitive and non-saturated inductive loads"

From a Crydom Whitepaper:-
"Solid State Relays (SSRs) and Solid State Contactors (SSCs) are ideally suited for
controlling dynamic loads such as motors"
http://www.crydom.com/en/tech/white-papers/ac_mc_whitepaper.pdf

I have a Resol Controller for my Solar Thermal, and it can vary the speed of the pump - I can set it in 10% increments from 30% to 100%. It uses a Solid State output, not a mechanical relay. Can you advise how this is achieved?


Thinking about it my solar thermal varies the pump speeds and there are inverters for motor speed so yes it is possible but in this this case we are talking solar power 'diverters' and these are not designed for inductive loads. Perhaps it is something to do with a minimum speed for a pump / motor and something like an immerson etc does not have this programmed in.
« Last Edit: April 09, 2020, 11:21:25 AM by Tinbum » Logged

85no 58mm solar thermal tubes, 28.5Kw PV, 3 x Sunny Backup 5048, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, Atmos wood gasification boiler, Brosley wood burner, 2000lt buffer tank and 250lt DHW
echase
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« Reply #20 on: April 20, 2020, 12:06:04 PM »

The Intelligent Immersion I2 or I2W has 2 outputs and a variable threshold down to zero.

Most of these diverters don't have fuse to protect the output SSR/triac/transistor so, if there is some external wiring fault, it blows the device and the warranty will not cover it. Basically it's then scrap. But the I2 has a fast fuse.

I retired from the company but I did design the I2.

We never recommended motor loads.  Motors with brushes might manage it but definitely not induction motors.
« Last Edit: April 20, 2020, 12:12:28 PM by echase » Logged
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