Coil Overheating Issue

We have an 220 VAC solenoid at one of our McQuay Chillers. It is used as part of its expansion valve. We have been facing overheating issues for a while.

Please find below its specifications:

Type: BF230CS,
Code No: 018F6282 220/230 VAC,
10 W, 50/60 Hz,
Ambient Temperature: 50 deg C
Applied Voltage: 220 VAC

At 220 VAC supply voltage, it reaches 80 deg C during operation which is beyond its maximum temperature (> 50 deg C) tolerance as mentioned above. It reaches this temperature within 25 minutes of operation and the current shoots up to 129 mA.

We conducted a test to see if its response would be different at 110 VAC. At 110 VAC supply voltage, it operates at 30 deg C i.e. it stays within acceptable temperature limits and it operates at a current of 46 mA. It is operating as per requirement at this supply voltage.

We have two queries with regards to its operation:

* Can solenoids rated for 220 VAC operation be operated at 110 VAC? Will operating it at 110 VAC have any long term effects or impact in the long run?

* If the answer to the above question is no, kindly suggest a coil with a rated operating voltage of 110 VAC suitable for our requirement as part of expansion valve.

As voltage is directly proportional to the core loss, it definitely should be increasing with Voltage. But the thing here is that when it is rated for 230V AC, there shouldn't be any problem with rising temperature!

The world is full of solenoid valves and their coils, from dozens of vendors, in literally, thousands, if not tens of thousands, of models with different specifications, so the answer is it depends on the specs for that specific coil.

Most solenoid coils are rated at a specific voltage and frequency. But several years ago, I know ASCO came out with a performance/premium line with coils that can handle 110/220Vac, but I'm told that the vast majority of ASCO's are not those models. I'm sure that there are other vendors who offer similar performance.

The temperature rise you see in operation is typical, the coil heats up. The ambient temperature spec is not the maximum coil temperature, it is a basis line for showing temperature rise.

The graph at the link below shows ASCO's temperature rating categories with respect to ambient temperature (from page 465 of the ASCO Engineering Guide)
https://s4.postimg.org/h9hzkhysd/ASCO_temperature_ratings.jpg

The complete ASCO Engineering Guide is here:
http://www.asco.com/ASCO Asset Library/asco-solenoid-valves-engineering-information.pdf

This Valcor note has some info on duty cycle and temperature:
http://www.valcor.com/valcor-technical-datasheets/tempdutycycle.pdf

Unless the coil is specifically rated for dual voltage, it will not function properly, if at all, for long at the wrong voltage.

The quickest way to burn out an AC solenoid coil is supply it with low Voltage. At rest the coil is low impedance, when the solenoid picks up and closes the magnetic circuit the impedance goes much higher.
Since yours seems to be getting extra hot it may not be pulling all the way in, pull it apart and check the travel. Check also that the shading ring is intact.

Does it make any unusual noise, e.g. loud buzzing?

Based on your current measurement at 220V the coil will be drawing 28 VA, which is more than twice the rated consumption. Which points to the magnet circuit not being "closed" due to some mechanical issue or dirt or a partially shorted coil.

Late in the game, but check that the armature is being pulled completely in. The coil is rated with the armature as a core. If the core is not there the inductance drops dramatically and the coil draws too much current. I've seen it before with both solenoids and contactors.

Regards
cww

If it is running that hot, you need to order a replacement solenoid to keep on hand.

The coil is rated for 50 Deg C in the shade.

The way you measure the coil temperature is critical.

A simple method is to measure the cold temperature and measure it after it heats up:

Resisitance of Copper R(T)/R(0)= [1+0.239*(T DegC)/100]

so R(80)= 1.09*R(20)... a 9% increase. If you get less that will tell you what the temp is.

80C is too hot as a rule.

I am from mobile phone, so replying very short.
Your coil impedance is more or less 2 kilo ohm.

If i want to keep temp at 50deg Celsius, then voltage of coil should be around 165 volt. So if i add a resistance in series, then resist as nce value should be around 1 kilo ohm with 6w thermal capacity.

You can add one res in series 1k ohm 6w.

Coil will operate without any problem. Only in case of voltage dip in system it will drop slightly earlier.