R3119N090A-TR-FE Voltage Detector

I've never used, nor needed, a voltage detector of any kind, so obviously my knowledge is limited.

Some voltage drop is always expected during motor startup, but dropping from 24V to below 9V is definitely excessive. At the moment, I see three possibilities:

1. Your power supply is unable to supply sufficient current. Use a heavier power supply and/or a significantly larger filter capacitor.

2. The switching device that turns the motor on is inadequate. Use a heavier duty device.

3. There is too much resistance in one or more parts of the path leading from the power supply through the switching device to the motor. use heavier and/or shorter wires and CB traces.

This device only uses 3.3µA of supply current, and its output is data only, which means very low current, so the lead/trace length to and from the device should not be a problem.

There are two versions of this electronic gismo ! You have

Type A. which controls Delay

Type E controls Sense.

Sure you are using the right version?

Also according to the Spec sheet they can be customised to customer requirements.

Maybe you should contact the Manufacturer direct and tell them what you are trying to achieve.

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I once designed a motor dynamic overload detector for a distributed chain of 480V 3ph motors for when chain conveyors got something caught. The inrush from the motors starting caused nuisance trips. The solution there was to supply the start signal to the detector and start a short timer that gated out the trip signal till the inrush normalized.

If you motor is smaller and on the DC bus, you might want to beef up the power supply and add some large enough caps to stabilize the bus from those transients. But unless there is something else that pulls it down, you might not even need the voltage watchdog anyway, otherwise, the timer or maybe monitoring the motor current along with the start is probably your only resort. So, an aside from this is that unless you use a 555 or something (what I used - it was 1982) you are into microcontroller territory, and you could just use an onboard comparator or A/D and just do it in firmware. That is a much better and more flexible solution.

Given your experience to date, I would find it hard to believe that circuit trace physics could even be remotely linked to your troubles.

i think the source is undeniably linked to your signal processing circuits. Motor starting current is a very slow event when compared to the bandwidth of the sensing circuit.

More information on your power supply design and the nature of the motor starts and other transients on your system could be helpful.

Perhaps monitoring the supply side of your 24 volt supply will decouple the regulation action of your power supply. You could then detect a power supply input problem likely to cause a problem, and calibrate your sensing parameters to detect the level likely to cause an unacceptable output level. You might have better luck by coupling the power supply load to the input voltage, in the cases where low power supply load allows the power supply to stay within output limits during a transient event.