Selectively reducing power draw

[JohnT]

Question: I’m going to have two devices that I need to be able to reduce their current draw. One is a simple fluid pump/heater/thermostat device 120VAC 1000W the other is a simple blower/heater/thermostat device 120VAC 900W. Sadly both are the lowest power draw devices of their kind I could find after extensive searches (and I’m neither smart enough Nor have the machine shop to build lower rated devices from scratch).. There will be several other devices (including more complex electronic devices) as well with an additional power draw of 120VAC 200W bringing tho total to 2100W, well within a 20A receptacle’s capacity. Being mobile renders a 20A receptacle’s availabIlity not a guarantee. I need to find a way to de-rate the 1000W pump/heater down to 850W and the blower/heater down to 750W for those times 15A receptacles are the only option. I know I will have to wire the more sensitive devices in parallel upstream of any amperage reducing devices, but what device can I use to reduce the amp draw of the pump/heater and blower/heater? Something tells me a simple resistor upstream of these two devices is not an answer.

Edit: I want to be able to selectively de-rate these items so that they draw 850W & 750W respectively when a 15A receptacle is the only source available rather than permanently de-rate them. I would prefer being able to run them at full power for when a 20+ amp receptacle does happen to be available

 

[JohnT]

Edit: I want to be able to selectively de-rate these items so that they draw 850W & 750W respectively when a 15A receptacle is the only source available rather than permanently de-rate them. I would prefer being able to run them at full power when a 20+ amp receptacle does happen to be available

 

[Diver300]

You can reduce the power that heaters take with a suitably rated lamp dimmer.

It would be best to leave the pump / blower running on the full 120 Vac, as those might not work at all with a lower voltage, or they might not like the odd waveform that most dimmers give out. The heater won't mind the waveform.

 

[ChrisP58]

One thing to keep in mind when reducing the power to a load, is that it won't be as powerful as it would be under full power.

For instance.
- A heater won't get as hot, or it will take longer to reach a specific temperature.
- A pump will take longer to move the same amount of material.
- A lamp won't give off the same amount of light.
etc.