DC hight current sensor measurment

[yassin.kraouch]

have you an idea on a current sensor that can measure up to 200A, and is not mounted on the PCB?? i found ACS758 but i can mount it on the PCB, i want on that can be mounted on the wire that support 200A ???

 

[mtwieg]

Is the current DC or AC? For AC you just want a current transformer, but for DC you'll want a hall effect current monitor. LEM makes some good ones that should fit your needs.

 

[yassin.kraouch]

yes it is DC and the current is about 200Amp, have you an idea of a low cost current sensor

 

[tpetar]

Such currents sugested only with Hall elemets!

Illustration examples:

 

[mtwieg]

yes it is DC and the current is about 200Amp, have you an idea of a low cost current sensor

Define "low cost." You're not going to get anything for a few dollars. Off the shelf sensors will be in the range of $10-$50, at least. You could try making your own, but getting robustness and decent accuracy will probably be difficult.

 

[RCinFLA]

I would not use ACS758 class open loop sensors for 200 amps. Based on their 6 microohm claim, just the thru strap would dissipate 6 watts which will make them very hot unless there is heat sink on the connecting thru strap. Achieving connected 6 micro-ohms is likely next to impossible. Their spec is likely made with massive copper clamps on each strap as it leaves the package.

For closed loop Hall effect sensor use something like Pacific Scientific CLSM-200LA. They are about $35. Closed loop sensor has a counter field coil driven by feedback amp that keeps the net field in the sensor core very low which avoids the magnet 'S' B-H curve from impacting accuracy, which the open loop sensor suffer from.

Pacific Scientific OECO - CLSM-200LA - Sensors - Sensors, Switches & Relays - Allied Electronics

Lowest cost solution would be a 500 amp resistive shunt, but that is still going to cost you about $25, and you lose isolation.

 

[luizsalomon]

In an electric car built by a friend of mine, he used a shunt resistance.
It was a plain copper bar, about 10 cm long by 5 cm wide and 1cm high.
So we used a 24bit ADC, with two ports: one on one end and the other at the other end of the bar. Then you just calculate the voltage drop.

Easy and cheap.

 

[tpetar]

When shunt is used there is influence on circuit and power waste. For higher amperage waste is bigger. If power source is batteries take this at mind.

Hall sensor dont have influence on circuit and power waste.
Also fire extinguisher not needed! :wink: