Equipment safeguards to protect equipment - Page 1
Forum section: electronics / repair

author: electronbean
author_rank: Contributor
timestamp: February 05, 2024, 11:17:06 pm
content: Hello,I have a circuit that powers both an extractor hood and a 230VAC outlet. When using my Rice Heater, I plug it into this outlet and turn on the extractor hood. The issue began when my first Rice Heater malfunctioned, initially attributing it to a manufacturing defect. However, after purchasing two more units from different brands and models, the problem persists. Always the Thermal Fuse blows up.I suspect the extractor hood may be causing the problem. You can find more details about the issue inhttps://www.eevblog.com/forum/repair/thermal-fuse/.I believe the extractor hood might be introducing noise or harmonics into the circuit, affecting the Rice Heater.My question is: Is there any equipment I can use to protect the Rice Heater by plugging it between the equipment and the outlet? I'm uncertain about the specific protection needed, but I suspect the extractor hood might be generating interference that affects the Rice Heater.I look around and I found this equipment:Surge ProtectorVoltage RegulatorPower ConditionerIsolation TransformerWhat do you think?Thank you

author: tggzzz
author_rank: Super Contributor
timestamp: February 05, 2024, 11:37:14 pm
content: Get a socket tester to verify that the connections are correct.Measure the voltage at the socket, under the various conditions you describe, e.g. with and without the cooler hood operating.Afteryou are sure the basics are sane, consider exotic things like harmonics.

author: electronbean
author_rank: Contributor
timestamp: February 06, 2024, 12:33:57 am
content: I have already taken these measurements. All good.Consequently, I've come here to seek assistance with identifying other potential sources of the problems.

author: tggzzz
author_rank: Super Contributor
timestamp: February 06, 2024, 01:34:59 am
content: There is no way equipment should fail as you describe. Either the equipment is grossly underspecified or the mains supply is grossly out of spec.I recommend you get a local electrician to investigate your problem. They will understand how thelocalelectricity supply behaves (surges etc), and will be able to check your installation. If there is a general problem in your locality, they will be able to recommend the appropriate course of action.Failing that, get the electricity supply company to verify the mains supply is within spec.

author: ArdWar
author_rank: Frequent Contributor
timestamp: February 06, 2024, 11:45:11 am
content: That would require a ridiculously bad EMI crap for a device to1) cause damage to other separate device2) of which pretty much a simple resistive load3) from a device that does not take that much power to begin withIt's more likely that your mains is bad to begin with, or you're just plain unlucky with your rice heaters.

author: tggzzz
author_rank: Super Contributor
timestamp: February 06, 2024, 11:55:10 am
content: Quote from: ArdWar on February 06, 2024, 11:45:11 amPrecisely.Given that this is the OP's second thread on the topic, I suspect they don't want that answer and will find ways to ignore it. kudos to the OP for mentioning it in their first postMany don't

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 06, 2024, 07:32:39 pm
content: Maybe perhaps the inductive load of the fume extractor and some other crap was leaking into the mains, which leaked into the rice cooker and caused some sort of problem?Maybe the fume hood was back feeding some sort of voltage spike crap into the rice cooker?Try installing an EMI filter with X class and Y class capacitors and then hook it up.Also if you have one, use a scope to probe the mains. (REMEMBER TO PROBE THE MAINS CORRECTLY WITH A SCOPE OR YOU'LL GET A BUNCH OF METAL SPLINTERS IN YOUR EYE BALLS)Report back.

author: CaptDon
author_rank: Super Contributor
timestamp: February 07, 2024, 02:20:07 pm
content: The motor and circuits of the extractor hood electrically should have no reason to trip the thermal fuse on the heater. Have you considered the extractor hood is disrupting airflow direction around the heater and the heater is getting excessively hot and tripping the thermal fuse?? It would seem that running the hood would cause a slightly lower mains voltage and not likely to be the cause of the thermal fuse failure. More likely an airflow direction problem around the heater. Possibly if the heater has its own internal circulator fan the mains voltage is to low and the internal fan is running to slow. It shouldn't take a rocket scientist or tons of postings to square this problem away?

author: electronbean
author_rank: Contributor
timestamp: April 23, 2024, 10:06:08 am
content: The suggestion about the air being too hot around the equipment is correct. I have positioned the equipment in such a way that it is elevated above the surface, at least 10cm from it, allowing for better air circulation. However, despite this setup, the thermal fuse continues to blow.I suspect the issue may be related to the extractor hood. The thermal fuse doesn't blow the first time the equipment is used. Over the past few weeks, I've had to replace the thermal fuse several times. Sometimes it blows after the third use, other times after the tenth, and sometimes after the sixth. The behavior seems random, but the conditions remain consistent (the extractor hood is always connected to the same circuit, and the rice cooker is suspended about 10cm above the surface).Do you have any ideas? I'm considering purchasing some equipment to connect between the appliance and the wall plug to protect against potential issues that may be occurring more frequently (I know, sounds stupid and random decision but I don't really don't know where to look - I don't have oscilloscope).Thank you.Side note: To those genuinely here to contribute to a constructive technical discussion, I extend my thanks. To others who come here to spread negativity, I suggest you find a more productive use of your time.