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Why does this microswitch datasheet specify a minimum load current?
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The Omron VX series datasheet mentions on page 6 that "Using a model for ordinary loads to open or close the contact of a micro load circuit may result in faulty contact.", and shows that their micro load models even still require a minimum of 1mA @ 5V. Their D3V datasheet goes further and explicitly marks the low end as being an "inoperable range". But neither datasheet explains why a microswitch would have a problem with a low load condition. Why is this, and what would happen if a microswitch was operated at loads lower than the minimum operating range?
switches datasheet low-power specifications
asked 1 hour ago
bdonlan
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up vote
2
down vote
favorite
The Omron VX series datasheet mentions on page 6 that "Using a model for ordinary loads to open or close the contact of a micro load circuit may result in faulty contact.", and shows that their micro load models even still require a minimum of 1mA @ 5V. Their D3V datasheet goes further and explicitly marks the low end as being an "inoperable range". But neither datasheet explains why a microswitch would have a problem with a low load condition. Why is this, and what would happen if a microswitch was operated at loads lower than the minimum operating range?
switches datasheet low-power specifications
asked 1 hour ago
bdonlan
1134
New contributor
bdonlan is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
2
This has been asked several time. Search for "wetting current". TL;DR: The contacts oxygenize and it needs a minium current and voltage to "burn" them free. Gold contacts typically have much lower minimal current.
– Andy
1 hour ago
Good question, I think it's related to the contact coating, micro load are gold coated and normal load are silver coated and probably has to do with silver oxidizing and needing a minimum current to break the oxide layer when contacting, the gold contact doesn't have this issue but might in other hand be more mechanically sensitive.
– Damien
1 hour ago
add a comment |Â
up vote
2
down vote
favorite
up vote
2
down vote
favorite
The Omron VX series datasheet mentions on page 6 that "Using a model for ordinary loads to open or close the contact of a micro load circuit may result in faulty contact.", and shows that their micro load models even still require a minimum of 1mA @ 5V. Their D3V datasheet goes further and explicitly marks the low end as being an "inoperable range". But neither datasheet explains why a microswitch would have a problem with a low load condition. Why is this, and what would happen if a microswitch was operated at loads lower than the minimum operating range?
switches datasheet low-power specifications
asked 1 hour ago
bdonlan
1134
New contributor
bdonlan is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
The Omron VX series datasheet mentions on page 6 that "Using a model for ordinary loads to open or close the contact of a micro load circuit may result in faulty contact.", and shows that their micro load models even still require a minimum of 1mA @ 5V. Their D3V datasheet goes further and explicitly marks the low end as being an "inoperable range". But neither datasheet explains why a microswitch would have a problem with a low load condition. Why is this, and what would happen if a microswitch was operated at loads lower than the minimum operating range?
switches datasheet low-power specifications
switches datasheet low-power specifications
asked 1 hour ago
bdonlan
1134
New contributor
bdonlan is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 1 hour ago
bdonlan
1134
New contributor
bdonlan is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 1 hour ago
bdonlan
1134
New contributor
bdonlan is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 1 hour ago
bdonlan
1134
asked 1 hour ago
bdonlan
1134
1134
New contributor
bdonlan is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
bdonlan is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
bdonlan is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
2
This has been asked several time. Search for "wetting current". TL;DR: The contacts oxygenize and it needs a minium current and voltage to "burn" them free. Gold contacts typically have much lower minimal current.
– Andy
1 hour ago
Good question, I think it's related to the contact coating, micro load are gold coated and normal load are silver coated and probably has to do with silver oxidizing and needing a minimum current to break the oxide layer when contacting, the gold contact doesn't have this issue but might in other hand be more mechanically sensitive.
– Damien
1 hour ago
add a comment |Â
2
This has been asked several time. Search for "wetting current". TL;DR: The contacts oxygenize and it needs a minium current and voltage to "burn" them free. Gold contacts typically have much lower minimal current.
– Andy
1 hour ago
Good question, I think it's related to the contact coating, micro load are gold coated and normal load are silver coated and probably has to do with silver oxidizing and needing a minimum current to break the oxide layer when contacting, the gold contact doesn't have this issue but might in other hand be more mechanically sensitive.
– Damien
1 hour ago
2
2
This has been asked several time. Search for "wetting current". TL;DR: The contacts oxygenize and it needs a minium current and voltage to "burn" them free. Gold contacts typically have much lower minimal current.
– Andy
1 hour ago
This has been asked several time. Search for "wetting current". TL;DR: The contacts oxygenize and it needs a minium current and voltage to "burn" them free. Gold contacts typically have much lower minimal current.
– Andy
1 hour ago
Good question, I think it's related to the contact coating, micro load are gold coated and normal load are silver coated and probably has to do with silver oxidizing and needing a minimum current to break the oxide layer when contacting, the gold contact doesn't have this issue but might in other hand be more mechanically sensitive.
– Damien
1 hour ago
Good question, I think it's related to the contact coating, micro load are gold coated and normal load are silver coated and probably has to do with silver oxidizing and needing a minimum current to break the oxide layer when contacting, the gold contact doesn't have this issue but might in other hand be more mechanically sensitive.
– Damien
1 hour ago
add a comment |Â
1 Answer
1
active
oldest
votes
up vote
4
down vote
accepted
The switch is available in Gold (Au) and Silver (Ag) alloy.
Gold allows switching of low voltage and current signals, such as measurements.
Silver allows switching of high voltage and current, such as power and coils.
This difference is because the contact material degrades over time and per switching action, and a low voltage might not be able to get any current though the high resistance oxidation layer on the contacts.
This why gold plated contacts exist. (Au)
However, high current arcing destroys the gold plating, which is why Silver Nickel + Gold plating exist (AgNi + Au) to get the best of both.
When using low current, the gold remains intact, but when switching high current the gold is destroyed and the properties of a Silver Nickel contact apply.
See also the Fundamentals of Relay Technology.
answered 1 hour ago
Jeroen3
10.1k1343
2
And there are AgNI + Au contacts where the gold coating is so thin that it only prevents oxidation while storage and gets mechanically destroyed after the first few switch cycles
– Andy
57 mins ago
So, if I understand this correctly, the actual failure mode is an increase in contact resistance over time resulting in the pull-up being too strong relative to the switch contact resistance? Wouldn't this be a violation of the contact resistance spec, or does >1mA of current have some sort of healing effect that removes the oxidation?
– bdonlan
11 mins ago
Found the answer in the PDF you linked: "In addition to the constant cleaning effect due to contact friction, this switching spark assumes the function of penetrating non-conductive contamination layers that are formed on the contact surfaces of power contacts."
– bdonlan
7 mins ago
add a comment |Â
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
accepted
The switch is available in Gold (Au) and Silver (Ag) alloy.
Gold allows switching of low voltage and current signals, such as measurements.
Silver allows switching of high voltage and current, such as power and coils.
This difference is because the contact material degrades over time and per switching action, and a low voltage might not be able to get any current though the high resistance oxidation layer on the contacts.
This why gold plated contacts exist. (Au)
However, high current arcing destroys the gold plating, which is why Silver Nickel + Gold plating exist (AgNi + Au) to get the best of both.
When using low current, the gold remains intact, but when switching high current the gold is destroyed and the properties of a Silver Nickel contact apply.
See also the Fundamentals of Relay Technology.
answered 1 hour ago
Jeroen3
10.1k1343
2
And there are AgNI + Au contacts where the gold coating is so thin that it only prevents oxidation while storage and gets mechanically destroyed after the first few switch cycles
– Andy
57 mins ago
So, if I understand this correctly, the actual failure mode is an increase in contact resistance over time resulting in the pull-up being too strong relative to the switch contact resistance? Wouldn't this be a violation of the contact resistance spec, or does >1mA of current have some sort of healing effect that removes the oxidation?
– bdonlan
11 mins ago
Found the answer in the PDF you linked: "In addition to the constant cleaning effect due to contact friction, this switching spark assumes the function of penetrating non-conductive contamination layers that are formed on the contact surfaces of power contacts."
– bdonlan
7 mins ago
add a comment |Â
up vote
4
down vote
accepted
The switch is available in Gold (Au) and Silver (Ag) alloy.
Gold allows switching of low voltage and current signals, such as measurements.
Silver allows switching of high voltage and current, such as power and coils.
This difference is because the contact material degrades over time and per switching action, and a low voltage might not be able to get any current though the high resistance oxidation layer on the contacts.
This why gold plated contacts exist. (Au)
However, high current arcing destroys the gold plating, which is why Silver Nickel + Gold plating exist (AgNi + Au) to get the best of both.
When using low current, the gold remains intact, but when switching high current the gold is destroyed and the properties of a Silver Nickel contact apply.
See also the Fundamentals of Relay Technology.
answered 1 hour ago
Jeroen3
10.1k1343
2
And there are AgNI + Au contacts where the gold coating is so thin that it only prevents oxidation while storage and gets mechanically destroyed after the first few switch cycles
– Andy
57 mins ago
So, if I understand this correctly, the actual failure mode is an increase in contact resistance over time resulting in the pull-up being too strong relative to the switch contact resistance? Wouldn't this be a violation of the contact resistance spec, or does >1mA of current have some sort of healing effect that removes the oxidation?
– bdonlan
11 mins ago
Found the answer in the PDF you linked: "In addition to the constant cleaning effect due to contact friction, this switching spark assumes the function of penetrating non-conductive contamination layers that are formed on the contact surfaces of power contacts."
– bdonlan
7 mins ago
add a comment |Â
up vote
4
down vote
accepted
up vote
4
down vote
accepted
The switch is available in Gold (Au) and Silver (Ag) alloy.
Gold allows switching of low voltage and current signals, such as measurements.
Silver allows switching of high voltage and current, such as power and coils.
This difference is because the contact material degrades over time and per switching action, and a low voltage might not be able to get any current though the high resistance oxidation layer on the contacts.
This why gold plated contacts exist. (Au)
However, high current arcing destroys the gold plating, which is why Silver Nickel + Gold plating exist (AgNi + Au) to get the best of both.
When using low current, the gold remains intact, but when switching high current the gold is destroyed and the properties of a Silver Nickel contact apply.
See also the Fundamentals of Relay Technology.
answered 1 hour ago
Jeroen3
10.1k1343
The switch is available in Gold (Au) and Silver (Ag) alloy.
Gold allows switching of low voltage and current signals, such as measurements.
Silver allows switching of high voltage and current, such as power and coils.
This difference is because the contact material degrades over time and per switching action, and a low voltage might not be able to get any current though the high resistance oxidation layer on the contacts.
This why gold plated contacts exist. (Au)
However, high current arcing destroys the gold plating, which is why Silver Nickel + Gold plating exist (AgNi + Au) to get the best of both.
When using low current, the gold remains intact, but when switching high current the gold is destroyed and the properties of a Silver Nickel contact apply.
See also the Fundamentals of Relay Technology.
answered 1 hour ago
Jeroen3
10.1k1343
answered 1 hour ago
Jeroen3
10.1k1343
answered 1 hour ago
Jeroen3
10.1k1343
answered 1 hour ago
Jeroen3
10.1k1343
10.1k1343
2
And there are AgNI + Au contacts where the gold coating is so thin that it only prevents oxidation while storage and gets mechanically destroyed after the first few switch cycles
– Andy
57 mins ago
So, if I understand this correctly, the actual failure mode is an increase in contact resistance over time resulting in the pull-up being too strong relative to the switch contact resistance? Wouldn't this be a violation of the contact resistance spec, or does >1mA of current have some sort of healing effect that removes the oxidation?
– bdonlan
11 mins ago
Found the answer in the PDF you linked: "In addition to the constant cleaning effect due to contact friction, this switching spark assumes the function of penetrating non-conductive contamination layers that are formed on the contact surfaces of power contacts."
– bdonlan
7 mins ago
add a comment |Â
2
And there are AgNI + Au contacts where the gold coating is so thin that it only prevents oxidation while storage and gets mechanically destroyed after the first few switch cycles
– Andy
57 mins ago
So, if I understand this correctly, the actual failure mode is an increase in contact resistance over time resulting in the pull-up being too strong relative to the switch contact resistance? Wouldn't this be a violation of the contact resistance spec, or does >1mA of current have some sort of healing effect that removes the oxidation?
– bdonlan
11 mins ago
Found the answer in the PDF you linked: "In addition to the constant cleaning effect due to contact friction, this switching spark assumes the function of penetrating non-conductive contamination layers that are formed on the contact surfaces of power contacts."
– bdonlan
7 mins ago
2
2
And there are AgNI + Au contacts where the gold coating is so thin that it only prevents oxidation while storage and gets mechanically destroyed after the first few switch cycles
– Andy
57 mins ago
And there are AgNI + Au contacts where the gold coating is so thin that it only prevents oxidation while storage and gets mechanically destroyed after the first few switch cycles
– Andy
57 mins ago
So, if I understand this correctly, the actual failure mode is an increase in contact resistance over time resulting in the pull-up being too strong relative to the switch contact resistance? Wouldn't this be a violation of the contact resistance spec, or does >1mA of current have some sort of healing effect that removes the oxidation?
– bdonlan
11 mins ago
So, if I understand this correctly, the actual failure mode is an increase in contact resistance over time resulting in the pull-up being too strong relative to the switch contact resistance? Wouldn't this be a violation of the contact resistance spec, or does >1mA of current have some sort of healing effect that removes the oxidation?
– bdonlan
11 mins ago
Found the answer in the PDF you linked: "In addition to the constant cleaning effect due to contact friction, this switching spark assumes the function of penetrating non-conductive contamination layers that are formed on the contact surfaces of power contacts."
– bdonlan
7 mins ago
Found the answer in the PDF you linked: "In addition to the constant cleaning effect due to contact friction, this switching spark assumes the function of penetrating non-conductive contamination layers that are formed on the contact surfaces of power contacts."
– bdonlan
7 mins ago
add a comment |Â
bdonlan is a new contributor. Be nice, and check out our Code of Conduct.
bdonlan is a new contributor. Be nice, and check out our Code of Conduct.
bdonlan is a new contributor. Be nice, and check out our Code of Conduct.
bdonlan is a new contributor. Be nice, and check out our Code of Conduct.
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2
This has been asked several time. Search for "wetting current". TL;DR: The contacts oxygenize and it needs a minium current and voltage to "burn" them free. Gold contacts typically have much lower minimal current.
– Andy
1 hour ago
Good question, I think it's related to the contact coating, micro load are gold coated and normal load are silver coated and probably has to do with silver oxidizing and needing a minimum current to break the oxide layer when contacting, the gold contact doesn't have this issue but might in other hand be more mechanically sensitive.
– Damien
1 hour ago