cornbread said:
...I think what you have is a 10 amp contact for a resistive load and 1.5 amp for a inductive load.
Not to say the continuous resistive rating for this relay is not 10 amps, but the 10 amp make rating is only referring to the make rating of an Inductive load, so we cannot really assume this to be a continuous rating for a resistive load.
A Resistive load will indeed have the same rating for make, break and continuous amps, while an Inductive load will have a different rating for make, break and continuous amps.
dogleg43 said:
...Is this the same thing as saying the contacts need to be rated for a 10 amp continuous load?...
No...
Example: A relay with a contact rating of 40 amps at 240VAC Resistive has a make, break and continuous rating of 40 amps each. The same relay contact, when switching an Inductive circuit, will have a different amperage for each of its make, break and continuous ratings. It will have a continuous rating of only 10 amps for an Inductive load at 240VAC; the MAKE rating at 240VAC will be 30 amps, however, the BREAK rating is only 3 amps at 240VAC.
So, if you are switching an Inductive load, the 10 amps make rating you have read does not necessarily imply that it is 10 amps for a continuous Inductive load. If the make is only 10 amps, then the continuous rating for an Inductive load might be less, more like 8 amps continuous, but not always. It depends a lot on which voltage you are working at. At 120VAC, an Inductive load on a contact could have a make rating of 60 amps, and a continuous rating of 10 amps. However, if we go up to 600VAC, then the make rating could drop to say 12 amps, and the continuous to around 10 amps. So at higher voltages, the difference between the make and continuous ratings is far less than at lower voltages.
The spec you've quoted above only matters if you are switching an Inductive load. If resistive, you need to find the continuous rating for a resistive load in the specs; this will also be its make and break rating.
More specific to bernie's info...
Arcing with inductive loads such as motors; when a circuit is applied to a winding, that winding creates a magnetic field and induction occurs. When the circuit is broken the magnetic field collapses, and this generates a voltage spike and creates an arc at the breaking point of the circuit's path. i.e. the contact. This is why, for inductive loads, the contact ratings differ for make, break and continuous compared to resistive loads which do not suffer the same effects. Both types of loads, of course, have their own drawbacks and suppression methods to overcome them.
Regards,
George