Maker Pro
Maker Pro

Creepage distances for aircraft power supplies

J

Joerg

Jan 1, 1970
0
Does anyone know where to find the creepage distances for 115V/400Hz
power supply circuit boards in civilian aircraft?

Similar to what IEC/UL60601 says for medical. I have the numbers for mil
but not sure whether civilian is the same. DO-160E is (to my surprise)
silent about this topic.
 
M

Martin Riddle

Jan 1, 1970
0
| Does anyone know where to find the creepage distances for 115V/400Hz
| power supply circuit boards in civilian aircraft?
|
| Similar to what IEC/UL60601 says for medical. I have the numbers for
mil
| but not sure whether civilian is the same. DO-160E is (to my surprise)
| silent about this topic.
|
| --
| Regards, Joerg
|
| http://www.analogconsultants.com/
|
| "gmail" domain blocked because of excessive spam.
| Use another domain or send PM.

Double or single insulation? If I recall, its 4mm single 8mm double. And
a whole other story above 150v.

Cheers
 
J

Joerg

Jan 1, 1970
0
Martin said:
| Does anyone know where to find the creepage distances for 115V/400Hz
| power supply circuit boards in civilian aircraft?
|
| Similar to what IEC/UL60601 says for medical. I have the numbers for
mil
| but not sure whether civilian is the same. DO-160E is (to my surprise)
| silent about this topic.
|
| --
| Regards, Joerg
|
| http://www.analogconsultants.com/
|
| "gmail" domain blocked because of excessive spam.
| Use another domain or send PM.

Double or single insulation? If I recall, its 4mm single 8mm double. And
a whole other story above 150v.

That sounds too high. Mil allows down to 1.5mm for low power stuff in
some situations (under 150V). Lower power usually meaning that it does
not exceed 50W. Medical is 4/8mm.

Do you remember what the standard was called?
 
M

Martin Riddle

Jan 1, 1970
0
| Martin Riddle wrote:
| > | > | Does anyone know where to find the creepage distances for
115V/400Hz
| > | power supply circuit boards in civilian aircraft?
| > |
| > | Similar to what IEC/UL60601 says for medical. I have the numbers
for
| > mil
| > | but not sure whether civilian is the same. DO-160E is (to my
surprise)
| > | silent about this topic.
| > |
| > | --
| > | Regards, Joerg
| > |
| > | http://www.analogconsultants.com/
| > |
| > | "gmail" domain blocked because of excessive spam.
| > | Use another domain or send PM.
| >
| > Double or single insulation? If I recall, its 4mm single 8mm double.
And
| > a whole other story above 150v.
| >
|
| That sounds too high. Mil allows down to 1.5mm for low power stuff in
| some situations (under 150V). Lower power usually meaning that it does
| not exceed 50W. Medical is 4/8mm.
|
| Do you remember what the standard was called?
|

60601-1
 
J

Joerg

Jan 1, 1970
0
Martin said:
| Martin Riddle wrote:
| > | > | Does anyone know where to find the creepage distances for
115V/400Hz
| > | power supply circuit boards in civilian aircraft?
| > |
| > | Similar to what IEC/UL60601 says for medical. I have the numbers
for
| > mil
| > | but not sure whether civilian is the same. DO-160E is (to my
surprise)
| > | silent about this topic.
| > |
| > | --
| > | Regards, Joerg
| > |
| > | http://www.analogconsultants.com/
| > |
| > | "gmail" domain blocked because of excessive spam.
| > | Use another domain or send PM.
| >
| > Double or single insulation? If I recall, its 4mm single 8mm double.
And
| > a whole other story above 150v.
| >
|
| That sounds too high. Mil allows down to 1.5mm for low power stuff in
| some situations (under 150V). Lower power usually meaning that it does
| not exceed 50W. Medical is 4/8mm.
|
| Do you remember what the standard was called?
|

60601-1

Well, yes, that's my home turf: Medical. But it is different for nearly
all other markets.
 
R

Rich Grise

Jan 1, 1970
0
Does anyone know where to find the creepage distances for 115V/400Hz power
supply circuit boards in civilian aircraft?

Similar to what IEC/UL60601 says for medical. I have the numbers for mil
but not sure whether civilian is the same. DO-160E is (to my surprise)
silent about this topic.

Well, whichever one it is, I'd say if you follow what the medical one
says, it should be stringent enough to cover airplanes. (unless there's
a military one). The only other concerned parties should be the people in
the airplane and the insurance company. ;-)

Good Luck!
Rich
 
J

Joerg

Jan 1, 1970
0
Rich said:
Well, whichever one it is, I'd say if you follow what the medical one
says, it should be stringent enough to cover airplanes. (unless there's
a military one). The only other concerned parties should be the people in
the airplane and the insurance company. ;-)

Well, the medical one costs too much space. And I've only got the
military regs, was hoping someone would know the civilian ones.
 
A

Archimedes' Lever

Jan 1, 1970
0
That sounds too high. Mil allows down to 1.5mm for low power stuff in
some situations (under 150V). Lower power usually meaning that it does
not exceed 50W. Medical is 4/8mm.

Do you remember what the standard was called?


It is probably less than the medical numbers, so if you go with the
medical numbers, you will likely be inside the mil/aviation numbers.

Atmospheric air at 70,000 feet has a higher breakdown voltage than at
sea level.
 
W

Wimpie

Jan 1, 1970
0
Does anyone know where to find the creepage distances for 115V/400Hz
power supply circuit boards in civilian aircraft?

Similar to what IEC/UL60601 says for medical. I have the numbers for mil
but not sure whether civilian is the same. DO-160E is (to my surprise)
silent about this topic.

Hello Joerg,

Your creepage and clearance distance depends (as you know) on Peak
Working voltage, Transient voltages, Insulation surface and
alltitude. Maybe IEC 60664-1 can help you (table A.2).

One example, up to 33000ft, for clearance, you need to multiply with
3.02. I assume the civilian values are derived from this std.

Best regards,

Wim
www.tetech.nl
PA3DJS
the address is ok when you remove abc.
 
W

Wimpie

Jan 1, 1970
0
Does anyone know where to find the creepage distances for 115V/400Hz
power supply circuit boards in civilian aircraft?

Similar to what IEC/UL60601 says for medical. I have the numbers for mil
but not sure whether civilian is the same. DO-160E is (to my surprise)
silent about this topic.

Hello Joerg,

After 12 hours my posting did not appear over here. I already sent you
a reply directly.

Creepage and Clearance distances depend on working voltage, maximum
transient voltage, surface characteristics of creepage paths and air
pressure.

IEC 60664-1 deals with these issues, many product standard derive
there creepage/clearance requirements from this std. Table A.2 gives
the multipliers for higher altitudes. For example for 33000 ft (10
km), the multiplier for clearance through air is 3.02.

Best regards,

Wim
PA3DJS
www.tetech.nl
The address is ok, but don't forget to cut abc.
 
L

legg

Jan 1, 1970
0
Does anyone know where to find the creepage distances for 115V/400Hz
power supply circuit boards in civilian aircraft?

Similar to what IEC/UL60601 says for medical. I have the numbers for mil
but not sure whether civilian is the same. DO-160E is (to my surprise)
silent about this topic.

You could do worse than to consult IEC60664, or even the ancient
VDE0804. These all have pressure/altitude information.

Aircraft standards tend to be controlled by conformance documents
relevent to the model, issued by their manufacturer. This is a pretty
specialized field of power conversion , possibly approached most
sensibly for the first time from the ground support or
test/diagnostics end.

In military standards, more emphasis is actually placed on creepage
and clearance at the connector set, where it is assumed that the most
fragile and concentrated safety interface will occur, not in the
built-in isolators or enclosed printed wiring.

MIL HDBK 5400 and NAVSO P-3641 make good reading on power assemblies
for hi-rel applications.

RL
 
J

Joerg

Jan 1, 1970
0
Wimpie said:
Hello Joerg,

After 12 hours my posting did not appear over here. I already sent you
a reply directly.

Thanks, Wim, it did appear over here. Also got your PM. Sometimes posts
propagate onto your ISP's server later than onto other. I've never quite
understood why.

Creepage and Clearance distances depend on working voltage, maximum
transient voltage, surface characteristics of creepage paths and air
pressure.

IEC 60664-1 deals with these issues, many product standard derive
there creepage/clearance requirements from this std. Table A.2 gives
the multipliers for higher altitudes. For example for 33000 ft (10
km), the multiplier for clearance through air is 3.02.

Thanks, I'll check that out this afternoon. Hopefully it will be on the
web somewhere, I only have the medical IEC/EN standards here on the
table. In English and French ;-)
 
J

Joerg

Jan 1, 1970
0
legg said:
You could do worse than to consult IEC60664, or even the ancient
VDE0804. These all have pressure/altitude information.

Aircraft standards tend to be controlled by conformance documents
relevent to the model, issued by their manufacturer. This is a pretty
specialized field of power conversion , possibly approached most
sensibly for the first time from the ground support or
test/diagnostics end.

I am afraid we may have to go that route. In the end everything neeeds
to be STC'd anyhow but we don't want to risk a black eye at that point.

In military standards, more emphasis is actually placed on creepage
and clearance at the connector set, where it is assumed that the most
fragile and concentrated safety interface will occur, not in the
built-in isolators or enclosed printed wiring.

MIL HDBK 5400 and NAVSO P-3641 make good reading on power assemblies
for hi-rel applications.

Thanks, RL. I've got the military ones here and was surprised they allow
down to 1.5mm for low power gear.
 
J

Joerg

Jan 1, 1970
0
Archimedes' Lever said:
It is probably less than the medical numbers, so if you go with the
medical numbers, you will likely be inside the mil/aviation numbers.

That's the problem, we do not have that much real estate here. Otherwise
I usually go with medical because it is stricter than pretty much
anything else.
 
Top