50 Hz-Timers vrs 60 Hz. Timers?

[falco]

Hi to everyones, Could someone help me with this problem?
We purchased two furnaces for heat treatment. The timers of this furnaces have on their surface just the specification "50 Hz". In my country electrical power supply is 60 Hz. According to the manufacturer the furnaces function pretty good with 60 Hz, but a Termographic analysis that I made show me a rise of temperature of 30 degree C over the enviromente temperature (The surface of the timers had a temperature of 60 C ). The timers are manufactured in Spain and I live in EL SALVADOR C.A.
In my opinion this timers are manufactured just for 50 Hz., is there a standard where it must be specified, wich parameter should be marked on the electrical data of those equipment? Which one is this standard "DIN, ANSI, IEEE etc.. I´m looking for something like "The operating frequencies should be marked on the surface of equipment....."
I will appreciate if someone can help me because we have´t pay yet our suppliers and don´t want to have troubles with this equipment. You can answer me also to My E mail
falcondt@yahoo.com or falco@citt.cdb.edu.sv
THanks a lot

 

[gunjan]

The supply system in spain i believe is 380V 50Hz i.e. 220V AC single phase. The electrical equipments usually are manufactured for the voltage variation of +/- 10% & fequency of +/- 5%. If your supply system exceeds this value then the equipment might get overheated and may be damaged over long run.
For the case of frequency it depends on the type of the timer you are using i.e. it is an electronic timer or it is motorised timer like synchronous timers. We are supplying the electronic timers of 50Hz with our m/cs to the countries having 60Hz supply & we have not yet received any complains as in electronic timers the ac voltage is converted to dc and used for time measurement. But in case of motorised timers the timer would work but you will not get the correct time, as the speed of the motor would chage with the frequency.

If u have any further doubts pls. inform.

 

[buzzp]

I would go by what the mfg told you. I believe you will not see much difference in temperature if you could do the same test at 50Hz. Remember they have to reduce this voltage down to a useable voltage for electronics (say 30 volts or less). If this is done using resistors then it will definately run hot. If it uses a transformer then it will run cooler but a 30C heat rise is not that significant. Usually the PCB is rated for at least 105C sometimes 130C. This is usually the limitation on temperature. So any part of the board can not be hotter than what the board is rated for. So if the ambient temp gets to 60C then this would allow a 45C heat rise (from the boards point of view). You took measurements on the outside of the unit so you can not use your 30C for this calculation. You would have to determine the hot spot on the board and measure the heat rise there to get a better number. Does the product have any safety agency approvals, like CE?
Worth Noting: If they use the zero cross from the AC line for timing purposes then this will give you a smaller 'time' than you will have if the timer is set at the same time and running on 50 Hz. Good luck.

 

[nbucska]

If the timer depends on line freq.:
for 60 Hz increase the time values to 1.2 times
If constant ( e.g. crystal):
do nothing <nbucska@pcperipherals.com>