relay voltage rating

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#3
poobah said:
Yes... there is generally a little "give" in the coil specs. The absolute limits should be listed in the relay's data sheet though. You ARE talking about thew coil rating right?

🙂
Click to expand...


yes I'm talking about the coil.

unfortunately, I can't see the voltage operating range in the datasheet. all I see is the 10V (nominal).

thank you.
 
#4
A 10 Volt relay would probably "pick up" at 6 Volts and "drop out" at around 4 Volts. So your safe at 9 Volts, easy, on the low side. Your limiter on the high side is power dissipation in the coil. You're safe to assume a +/- 10% on coil voltage.

🙂
 
#8
Hi,
it looks like the low operate voltage using 182r and 32.5mA is about 6V. Well below your 9.5V.

The release voltage is only quoted as the minimum, in other word,s the voltage below which you must reduce to guarantee release.
The maximum release is what some relays will start to drop out at. You will need to measure this for your relay.
 
#11
Yes you can...

Be very mindful of one thing that relates to switches... of any type... toggles, relays, etc... The AC voltage and current ratings have NOTHING to do with the DC ratings. AC circuits have a big advantage... every 8.3 or 10 milliseconds the current goes to zero. This helps extinguish the arc. So... DC ratings for voltage and current are always much lower for the same relay (with a few exceptions).

Where are you wanting to use these relays? There are some things you should know about low level circuits maybe.

🙂
 
#12
poobah said:


Where are you wanting to use these relays? There are some things you should know about low level circuits maybe.

🙂
Click to expand...


I am planning to use this relay to turn-on the primaries for the B+ transformer. I will connect the primaries to the "normally-open" pins.

this is the circuit: http://myweb.tiscali.co.uk/nuukspot/decdun/gc/555delay2.gif

I have a separate 9V transformer for the amp tubes' heaters. I'll use the voltage (which varies from 9.5 to 10.3 according to simetrix) on the 1st cap as +V input to the NE555.
 
#13
That sounds fine...

Consider carefully your inrush currents at turn on.

The amount of current the relay must open is actually more important than the closure current. Do you have PSUDII?

This can give you inrush roughly...
 
#14
poobah said:
That sounds fine...

Consider carefully your inrush currents at turn on.

The amount of current the relay must open is actually more important than the closure current. Do you have PSUDII?

This can give you inrush roughly...
Click to expand...

I will be using an ntc thermistor at the primary. should that affect the operation?
 
#15
Yes,

That will help greatly. You can push the amperage ratings a wee bit where inrush is concerned... maybe a factor of 2 would be prudent. It is the interrupting (opening) ratings that you can't ignore.

Now, the relays aren't characterized that way... they give you one rating... illegitimate offsprings! You can generally assume the ratings refer to opening and not closing.

🙂
 
#18
just found this datasheet(http://relays.tycoelectronics.com/datasheets/d2n.pdf)



ul contact rating:
30 Vdc / 1.0 A
100 Vdc / 0.3 A
125 Vac / 0.5 A for 150 mW and 200 mW coil
125 Vac / 1.0 A for 400 mW and 500 mW coil

does that mean I can't use 240VAC on it? current draw would be less than 500mA for the B+ supply and the amp current load (not including heaters as the amp tube's heaters are powered using a 2nd transformer).
 
#20
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