SSR Solid-state relay selection guide

How to select suitable Solid state relay (ssr):

1) For new customers or customers who have never used solid-state products.

Solution: First determine whether it is a solid-state relay or a voltage regulator, single-phase or three-phase, and then ask the customer what load it is used on, the power and working voltage of the load.

Based on this information, our sales staff can recommend the corresponding SSR to the customer.

 

2) For old customers or customers who have used solid-state products

Solution: Ask the customer to send the product picture, and we can choose the corresponding SSR according to it. To be on the safe side, it is best to ask the customer what equipment it is used on, the power and working voltage of the equipment, because some companies will tamper with the label to prevent others from replacing it, and write the actual high-current product as a small current.

 

Common sense about solid-state relays:

The specification name of the solid-state relay is selected according to the specifications of the thyristor/Triac inside the product; for example, a 150A module means that there is a 150A thyristor inside the module; anyone with actual use experience knows that a 150A thyristor cannot pass a 150A current; there is a safety margin issue here. When selecting products, different margins should be left on the current level according to the nature of the load.

1. For resistive loads, you can select 2 times the load current, that's, Load's current x 2 = SSR's current.

2. For inductive loads, you can select 5 times the load current, 5~7 times.

3. For capacitive loads, you should select 10 times or even more.

 

Selection method for motor forward and reverse solid-state relay modules:

Motor power/voltage/1.732=actual current

Actual current*6~10 times=rated current of forward and reverse module

 

Selection of fast fuses:

The ratio is 60%-80%, for example, for 10A of SSR, select a fuse of 6-8A.