Current usage with multiple PWM controlled motors

I have a circuit that can use 25 A of current max, it is on a 25 A fuse. I am looking to control 4 DC brushless motors using ESC's. The trouble is that the motors are rated at 7A max current. I know that ESC's use a PWM signal to control the speed of the motors, so that means when the voltage is High in the PWM pulse the current will be ~7A for that period of time. I am worried that if I run all 4 motors (even on low speed) all at once, if the PWM signals all go high at the same time then the fuse will blow. Is this idea correct and if so what can I do to avoid this happening?

Further info: I am using these motors and they will be driving a propeller for a ROV. The manual for the esc is here, I believe the PWM frequency is 2Khz (they refer to it as operating frequency so I am not 100% sure).

• They also all need to stall. Max current is at full stall, idle current is at no stall or load. – Ignacio Vazquez-Abrams Nov 3 '14 at 0:40
• You should be careful with the tolerances of the parts. if your circuit can take 25A maximum, maybe you should use a fuse that blows at 22.5A (10% tolerance). That way, your fuse actually protects the circuit, which it doesn't the other way around because it actually takes a (short) time to "activate". – QuantumFlux Nov 3 '14 at 1:33
• Just because a motor is 'rated' for a particular max current doesn't mean that it will draw that much. Which motors do you have, and what are they driving? Also what is the PWM frequency of your ESC's? Do they have current limiting? – Bruce Abbott Nov 3 '14 at 3:12
• I am using these motors and they will be driving a propeller for a ROV. The manual for the esc is here, I believe the PWM frequency is 2Mhz (they refer to it as operating frequency so I am not 100% sure). I can't find anything about current limiting. – Jabbath Nov 3 '14 at 3:44
• To correct my previous comment, the frequency is 2Khz. – Jabbath Nov 3 '14 at 3:52