I got this relay from a scrap electronic part. Please tell me how to read its specification from the writings on it.
NOTE: Its the snaps of two sides of the same relay, not the pictures of two different relays.
Electronic – Identify the specifications of a relay from the writings on it
relay
Related Solutions
These relays contain a permanent magnet that supplements the magnetic flux of the coil. The permanent magnet supplies flux to either of two permeable paths than can be completed by an armature. To transfer the armature and its associated contacts from one position to the other requires energizing current through the electromagnetic coil using the correct polarity.
This principle is illustrated by the two magnetic circuit configurations below.
Energization of the coil by a current pulse of proper polarity reverses the flux in the iron structure of the relay; in the other, flux in the armature is reversed. The number of ampere turns provided by the coil must be sufficient to overcome the reluctance of the open pole gap (see dotted line flux path). One advantage of this type of relay is the capability of latching operation where the contacts remain in the last position without continued application of electromagnetic power. It also augments the amount of armature force available with a given relay size and input power.
Polarized relays are usually small, have faster operate and release times, and are more resistant to shock and vibration forces.
- Combining several relays in parallel is not good, because the contacts do not switch at exactly the same time, and it will cause arcing at the faster one. Another thing is that the motor is an inductive load and needs more current than the rated \$15\,\mathrm{A}\$ during startup.
- Without modifying the existing circuit, it can be done with another relay with 12V coil and contacts rated for inrush current of the motor.
Edit: Two 10A relays in series can still carry only 10A. Theoretically it should be possible to double the current by merging more relays to operate like one larger relay, but is not possible as described above.
Possible wiring can be done like this, for example with 30A or 40A automotive relays:
Best Answer
It's a 12V relay (it clearly says "12V DC").
The picture on the left also says 5A @ 250V AC. That's something, but relays are quite complex and have many important parameters.
In that sense the other one is easier. It says "Takamisawa" and that's a Fujitsu brand. For the rest just make some guesses. Google for "Takamisawa 12MB". Bingo! We get hits which also say "VS", and that's also on the relay, so the type is probably "VS 12 MB". On the Fujitsu website look for power relays. We're on the right track, because there is indeed a "VS" series.
Now we have the datasheet we can find just anything we need to know. Like your question about 9V. They're 12V relays, will 9V be enough in the first place? Coil ratings are on page 3. This is a standard device (high sensitive types are "SMB" instead of "MB"). The table says that the "Must operate voltage" is 8.4V, so the 9V is sufficient, but doesn't give you much headroom. If you switch the relay with a transistor you'll have a few hundred millivolts voltage drop over the transistor and if the 9V has some tolerance too the relay may not operate! A MOSFET as switching element may be a better choice than a BJT. A low \$R_{DS(ON)}\$ type like the NTR4170N (just a random type) will have a voltage drop of just a few mV.
Coil resistance is 200\$\Omega\$, so current will be \$I = \frac{V}{R} = \frac{9V}{200\Omega} = 45mA\$. Power is then only 405mW, while the rated power is 720mW, so it's clear that you're near the limits.
Bottom line: use anything printed on the relay + your imagination, and you'll often find any information you need.
Q & A (from comments)
Q: What is the difference between coil's Rated power and Operate power?
A: Operate Power is the power at the minimum required voltage ("Must Operate"): \$\frac{(8.4V)^2}{200Ω}\$=350mW. Rated Power is the power at the nominal voltage: \$\frac{(12V)^2}{200Ω}\$=720mW. If you can't work at the rated voltage, at least try to stay as far as possible above Must Operate Voltage; this is the absolute minimum for guaranteed operation.